crypto/elliptic: call IsOnCurve via the interface.
crypto/elliptic: call IsOnCurve via the interface.

https://go-review.googlesource.com/#/c/2421/ contains an unfortunate
slip where IsOnCurve is called on the CurveParams rather than the curve.
This doesn't really matter, but it's a pain for people doing tricks with
crypto/elliptic and means that 1.5 would be a regression for them
without this change.

See https://groups.google.com/forum/#!topic/golang-dev/i8OPUTYctOk

Change-Id: Ifa5f25f9a95d7484cb53d4883cfd78dc58a0f9a7
Reviewed-on: https://go-review.googlesource.com/12506
Reviewed-by: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

snowsnail/go,arschles/golang-go,nakedgc/go,derekmarcotte/go,qskycolor/go,NunoEdgarGub1/go,vsdutka/go,malvira/go,codestation/go,willjunspecial/go,fjballest/golang,danielsoro/go,xinhuang327/go,xiaobodu/go,myPublicGit/go,ObjectiveJoe/go,Stan-Lin-/go,mbrukman/go,pgmreddy/go,AALEKH/go,chinanjjohn2012/go,CAFxX/go,cyberroadie/go,miolini/go,gohin/go,skatsuta/go,sndnvaps/go,samanalysis/go,zouchao2010/go,ichu501/go,samanalysis/go,dafyddcrosby/go,constantine001/go,stormltf/go,alash3al/go,mbrukman/go,CodyGuo/go,ericsnowcurrently/go,4ad/go,Jordanzuo/go,Young55555/go,cloudrain21/go,codestation/go,jasonxiong/go,constantine001/go,chinanjjohn2012/go,constantine001/go,rachtsingh/gogojuice,jasonxiong/go,devpadawan/go,springning/go,malvira/go,jmptrader/go,qskycolor/go,odeke-em/go,cloudflare/go,jasonxiong/go,mwhudson/go,rentongzhang/go,arschles/golang-go,zhangg/go,willjunspecial/go,kakuhiroshi/go,ObjectiveJoe/go,deft-code/go,shazow/go,Young55555/go,jacobhaven/go,ganboing/go-esx,jonahglover/go,mwhudson/go,arschles/golang-go,WIZARD-CXY/go,CiscoCloud/go,stormltf/go,vsdutka/go,CarterTsai/go,ErikDubbelboer/go,josharian/go,albertjin/golang-go,theass/go,joshsammut/go,RBEGamer/go,mbrukman/go,nawawi/go,lihuanghai/go,mgyenik/go,Endika/go,Young55555/go,ifagnosticism/go,ichu501/go,gdey/go,NunoEdgarGub1/go,snowsnail/go,monetate/go,Samurais/go,theif519/go,XuYunnan/go,dgnorton/go,dterei/go,roth1002/go,dpatel06/go,qskycolor/go,zhangg/go,cyberroadie/go,ifagnosticism/go,Badredapple/go,zouchao2010/go,cookerzhu/go,b54898533/go,wangfakang/go-1,kim-racktop/go,sndnvaps/go,skatsuta/go,Pulgafree/go,snowsnail/go,likesea/go,jmptrader/go,danielsoro/go,fjballest/golang,alex-zhang/go,AALEKH/go,akutz/go,famorted/go,theass/go,jdeng/go,NunoEdgarGub1/go,youprofit/go,GeorgiCodes/go,WIZARD-CXY/go,chinanjjohn2012/go,youprofit/go,RBEGamer/go,monetate/go,jacobxk/go,malvira/go,rentongzhang/go,xinhuang327/go,dgnorton/go,b54898533/go,jonasi/go,suncycheng/go,slavau/go,ImJasonH/go,chinanjjohn2012/go,miolini/go,danycoro/go,mdp/go,sinuos/go,jefby/go,suncycheng/go,springning/go,ganboing/go-esx,cloudflare/go,CAFxX/go,donnel6809/go,4ad/go,golang/go,deft-code/go,vishsingh/go,yasarkunduz/go,zcwfeng/go,jdhenke/go,g522342435/go,cainiaocome/go,Young55555/go,yangzhongj/go,cainiaocome/go,Badredapple/go,cloudrain21/go,deft-code/go,qskycolor/go,sndnvaps/go,polyverse-security/go,mgyenik/go,WIZARD-CXY/go,shines77/go,cookerzhu/go,Stan-Lin-/go,jacobsa/go,yuhengye/go,jefby/go,jameskumar/go,jonasi/go,momchil-velikov/go,snowsnail/go,famorted/go,cloudrain21/go,cloudflare/go,andrewchambers/go,dterei/go,theif519/go,albertjin/golang-go,danielsoro/go,andrewchambers/go,kakuhiroshi/go,willjunspecial/go,cainiaocome/go,wangfakang/go-1,albertjin/golang-go,dterei/go,Stan-Lin-/go,linux-on-ibm-z/go,polyverse-security/go,Endika/go,theass/go,snowsnail/go,andrewchambers/go,shines77/go,nawawi/go,vsekhar/elastic-go,vsdutka/go,albertjin/golang-go,alash3al/go,leeric92/go,miolini/go,jacobsa/go,vishsingh/go,nakedgc/go,ericsnowcurrently/go,Samurais/go,4ad/go,jdhenke/go,mgyenik/go,sosop/go,nawawi/go,snowsnail/go,arschles/go-1,mdp/go,honsiorovskyi/go,RBEGamer/go,XuYunnan/go,slavau/go,lihuanghai/go,samanalysis/go,JioCloud/go,sndnvaps/go,myPublicGit/go,ifagnosticism/go,danycoro/go,linux-on-ibm-z/go,jacobhaven/go,CarterTsai/go,jefby/go,derekmarcotte/go,shazow/go,shines77/go,jonathanmarvens/go,mwhudson/go,linux-on-ibm-z/go,sndnvaps/go,donnel6809/go,fjballest/golang,arschles/go-1,binarycrusader/go,cainiaocome/go,ImJasonH/go,CodyGuo/go,shazow/go,rachtsingh/gogojuice,vanloswang/go,WIZARD-CXY/go,gdey/go,ErikDubbelboer/go,stormltf/go,CodyGuo/go,polyverse-security/go,devpadawan/go,deft-code/go,stormltf/go,youprofit/go,lihuanghai/go,mgyenik/go,WIZARD-CXY/go,skotti/go,odeke-em/go,donnel6809/go,ImJasonH/go,christopher-henderson/Go,leeric92/go,famorted/go,binarycrusader/go,gdey/go,Young55555/go,jonathanmarvens/go,goodlang/good,Pulgafree/go,rachtsingh/gogojuice,lihuanghai/go,cookerzhu/go,ichu501/go,roth1002/go,jonahglover/go,parkdy/go,miolini/go,Young55555/go,parkdy/go,ganboing/go-esx,Cofyc/go,albertjin/golang-go,Stan-Lin-/go,uileyar/go,Badredapple/go,NichoZhang/go,xujianhai/go,RBEGamer/go,wangfakang/go-1,slavau/go,b54898533/go,momchil-velikov/go,youprofit/go,wangfakang/go-1,jacobsa/go,myPublicGit/go,Cofyc/go,cyberroadie/go,shazow/go,baiyunping333/go,greyhwndz/go,odeke-em/go,zcwfeng/go,chinanjjohn2012/go,jasonxiong/go,parkdy/go,Cofyc/go,zcwfeng/go,Cofyc/go,mdp/go,lihuanghai/go,undergrowthlinear/go,jameskumar/go,honsiorovskyi/go,dterei/go,Endika/go,linux-on-ibm-z/go,myPublicGit/go,jacobhaven/go,mgyenik/go,alex-zhang/go,zcwfeng/go,linux-on-ibm-z/go,danielsoro/go,jacobsa/go,vishsingh/go,yangzhongj/go,chinanjjohn2012/go,vsdutka/go,Cofyc/go,jmptrader/go,g522342435/go,gohin/go,danycoro/go,ifagnosticism/go,monetate/go,cookerzhu/go,Samurais/go,arschles/go-1,jasonxiong/go,baiyunping333/go,malvira/go,jefby/go,yangzhongj/go,JioCloud/go,sosop/go,albertjin/golang-go,qskycolor/go,alex-zhang/go,ifagnosticism/go,parkdy/go,vanloswang/go,gohin/go,nawawi/go,cnbin/go,skatsuta/go,jmptrader/go,mbrukman/go,springning/go,danielsoro/go,Cofyc/go,sinuos/go,samanalysis/go,willjunspecial/go,jdeng/go,springning/go,polyverse-security/go,stormltf/go,momchil-velikov/go,Samurais/go,pgmreddy/go,jonahglover/go,CiscoCloud/go,ericsnowcurrently/go,nawawi/go,yangzhongj/go,dpatel06/go,greyhwndz/go,cnbin/go,cloudrain21/go,yasarkunduz/go,alash3al/go,sosop/go,cloudflare/go,willjunspecial/go,Stan-Lin-/go,binarycrusader/go,jonasi/go,CarterTsai/go,CarterTsai/go,joshsammut/go,yuhengye/go,NichoZhang/go,xiaobodu/go,xiuzhifu/go,danycoro/go,parkdy/go,fjballest/golang,pgmreddy/go,springning/go,cloudrain21/go,snowsnail/go,Cofyc/go,codestation/go,baiyunping333/go,dpatel06/go,zhangg/go,mikekap/go,jefby/go,leeric92/go,nakedgc/go,jacobsa/go,vsekhar/elastic-go,Jordanzuo/go,alash3al/go,monetate/go,kevinc0825/go,CiscoCloud/go,dpatel06/go,cainiaocome/go,GeorgiCodes/go,likesea/go,alex-zhang/go,jacobhaven/go,GeorgiCodes/go,sosop/go,slavau/go,snowsnail/go,andrewchambers/go,zcwfeng/go,baiyunping333/go,danielsoro/go,yangzhongj/go,jonathanmarvens/go,honsiorovskyi/go,sndnvaps/go,samanalysis/go,jameskumar/go,baiyunping333/go,rentongzhang/go,josharian/go,cookerzhu/go,dterei/go,jacobxk/go,vsekhar/elastic-go,Cofyc/go,ichu501/go,xiuzhifu/go,kevinc0825/go,samanalysis/go,pgmreddy/go,yasarkunduz/go,sinuos/go,XuYunnan/go,kevinc0825/go,CodyGuo/go,cookerzhu/go,ganboing/go-esx,XuYunnan/go,Badredapple/go,devpadawan/go,ericsnowcurrently/go,Samurais/go,zhangg/go,NichoZhang/go,slavau/go,miolini/go,ImJasonH/go,mikekap/go,alash3al/go,monetate/go,rentongzhang/go,cookerzhu/go,ErikDubbelboer/go,codestation/go,CAFxX/go,jdhenke/go,roth1002/go,theif519/go,greyhwndz/go,dgnorton/go,jmptrader/go,dpatel06/go,xinhuang327/go,CodyGuo/go,4ad/go,nawawi/go,rachtsingh/gogojuice,greyhwndz/go,monetate/go,kakuhiroshi/go,goodlang/good,shazow/go,Charlesdong/go-1,skotti/go,derekmarcotte/go,jdeng/go,goodlang/good,monetate/go,honsiorovskyi/go,akutz/go,jefby/go,NichoZhang/go,nawawi/go,gohin/go,qskycolor/go,CAFxX/go,leeric92/go,theif519/go,odeke-em/go,gohin/go,CarterTsai/go,ericsnowcurrently/go,CiscoCloud/go,xiuzhifu/go,andrewchambers/go,kim-racktop/go,beealone/go,Jordanzuo/go,dpatel06/go,cainiaocome/go,malvira/go,g522342435/go,ichu501/go,Charlesdong/go-1,rentongzhang/go,Charlesdong/go-1,cainiaocome/go,b54898533/go,uileyar/go,sinuos/go,NichoZhang/go,Endika/go,dafyddcrosby/go,CodyGuo/go,ImJasonH/go,ObjectiveJoe/go,AALEKH/go,suncycheng/go,ericsnowcurrently/go,momchil-velikov/go,goodlang/good,GeorgiCodes/go,NichoZhang/go,greyhwndz/go,JioCloud/go,rachtsingh/gogojuice,slavau/go,cnbin/go,jacobsa/go,slavau/go,derekmarcotte/go,donnel6809/go,constantine001/go,dafyddcrosby/go,springning/go,jacobhaven/go,fjballest/golang,willjunspecial/go,miolini/go,AALEKH/go,Young55555/go,XuYunnan/go,arschles/go-1,akutz/go,shines77/go,suncycheng/go,myPublicGit/go,josharian/go,jefby/go,zouchao2010/go,vishsingh/go,polyverse-security/go,wangfakang/go-1,mikekap/go,RBEGamer/go,shines77/go,mdp/go,kim-racktop/go,cookerzhu/go,rentongzhang/go,dterei/go,ericsnowcurrently/go,Stan-Lin-/go,baiyunping333/go,xujianhai/go,dterei/go,g522342435/go,xiuzhifu/go,stormltf/go,gdey/go,derekmarcotte/go,xinhuang327/go,beealone/go,devpadawan/go,alex-zhang/go,CarterTsai/go,skotti/go,NunoEdgarGub1/go,mdp/go,mwhudson/go,danycoro/go,nawawi/go,Young55555/go,Badredapple/go,GeorgiCodes/go,lihuanghai/go,dgnorton/go,deft-code/go,zouchao2010/go,linux-on-ibm-z/go,likesea/go,devpadawan/go,jmptrader/go,NunoEdgarGub1/go,ichu501/go,undergrowthlinear/go,youprofit/go,GeorgiCodes/go,Charlesdong/go-1,ganboing/go-esx,josharian/go,mdp/go,arschles/golang-go,jdeng/go,fjballest/golang,yuhengye/go,kevinc0825/go,mikekap/go,vsdutka/go,theif519/go,alex-zhang/go,dpatel06/go,leeric92/go,xinhuang327/go,ericsnowcurrently/go,lihuanghai/go,kim-racktop/go,willjunspecial/go,danycoro/go,CAFxX/go,slavau/go,xiaobodu/go,derekmarcotte/go,ObjectiveJoe/go,deft-code/go,danycoro/go,momchil-velikov/go,shines77/go,gohin/go,CiscoCloud/go,undergrowthlinear/go,yangzhongj/go,theass/go,donnel6809/go,b54898533/go,jdhenke/go,goodlang/good,golang/go,monetate/go,suncycheng/go,beealone/go,uileyar/go,Jordanzuo/go,JioCloud/go,rentongzhang/go,constantine001/go,jonathanmarvens/go,ErikDubbelboer/go,mikekap/go,devpadawan/go,samanalysis/go,jacobhaven/go,goodlang/good,mbrukman/go,cnbin/go,cloudflare/go,uileyar/go,ifagnosticism/go,mgyenik/go,sosop/go,arschles/go-1,andrewchambers/go,kevinc0825/go,mwhudson/go,jameskumar/go,gohin/go,CiscoCloud/go,baiyunping333/go,lihuanghai/go,momchil-velikov/go,joshsammut/go,golang/go,dafyddcrosby/go,jasonxiong/go,Badredapple/go,qskycolor/go,albertjin/golang-go,constantine001/go,theif519/go,4ad/go,undergrowthlinear/go,donnel6809/go,g522342435/go,joshsammut/go,nakedgc/go,dafyddcrosby/go,ganboing/go-esx,Pulgafree/go,jonasi/go,ErikDubbelboer/go,arschles/golang-go,yuhengye/go,xiuzhifu/go,arschles/go-1,cnbin/go,jonasi/go,devpadawan/go,myPublicGit/go,4ad/go,yuhengye/go,shines77/go,vsekhar/elastic-go,binarycrusader/go,leeric92/go,cloudflare/go,WIZARD-CXY/go,pgmreddy/go,kakuhiroshi/go,XuYunnan/go,jonathanmarvens/go,honsiorovskyi/go,arschles/golang-go,xujianhai/go,JioCloud/go,akutz/go,jacobxk/go,mbrukman/go,sinuos/go,jmptrader/go,ImJasonH/go,mbrukman/go,baiyunping333/go,likesea/go,rachtsingh/gogojuice,jameskumar/go,yuhengye/go,honsiorovskyi/go,zhangg/go,constantine001/go,skotti/go,sosop/go,cloudflare/go,WIZARD-CXY/go,joshsammut/go,4ad/go,rachtsingh/gogojuice,Jordanzuo/go,XuYunnan/go,jonathanmarvens/go,vishsingh/go,wangfakang/go-1,cnbin/go,likesea/go,RBEGamer/go,akutz/go,shazow/go,xinhuang327/go,binarycrusader/go,jonahglover/go,ifagnosticism/go,Jordanzuo/go,golang/go,alash3al/go,jmptrader/go,XuYunnan/go,likesea/go,cyberroadie/go,mikekap/go,shazow/go,jacobhaven/go,zhangg/go,jasonxiong/go,kakuhiroshi/go,danielsoro/go,NichoZhang/go,greyhwndz/go,cloudflare/go,g522342435/go,donnel6809/go,alash3al/go,cyberroadie/go,vsekhar/elastic-go,kakuhiroshi/go,theass/go,CarterTsai/go,myPublicGit/go,parkdy/go,skotti/go,momchil-velikov/go,dgnorton/go,kakuhiroshi/go,jacobxk/go,codestation/go,parkdy/go,parkdy/go,vanloswang/go,zouchao2010/go,ImJasonH/go,vsdutka/go,akutz/go,donnel6809/go,Charlesdong/go-1,theass/go,leeric92/go,CarterTsai/go,jameskumar/go,codestation/go,kakuhiroshi/go,jonahglover/go,ganboing/go-esx,suncycheng/go,Badredapple/go,yasarkunduz/go,vsekhar/elastic-go,jdeng/go,famorted/go,Samurais/go,GeorgiCodes/go,rachtsingh/gogojuice,joshsammut/go,gdey/go,joshsammut/go,akutz/go,Endika/go,shazow/go,xiaobodu/go,jacobxk/go,NunoEdgarGub1/go,skotti/go,wangfakang/go-1,likesea/go,ObjectiveJoe/go,josharian/go,ifagnosticism/go,Pulgafree/go,samanalysis/go,miolini/go,ichu501/go,b54898533/go,sndnvaps/go,danielsoro/go,gdey/go,dafyddcrosby/go,CodyGuo/go,ObjectiveJoe/go,jameskumar/go,malvira/go,springning/go,CAFxX/go,deft-code/go,pgmreddy/go,momchil-velikov/go,AALEKH/go,youprofit/go,vanloswang/go,jameskumar/go,WIZARD-CXY/go,AALEKH/go,kim-racktop/go,suncycheng/go,mgyenik/go,golang/go,Stan-Lin-/go,uileyar/go,wangfakang/go-1,zcwfeng/go,vsekhar/elastic-go,jdeng/go,arschles/go-1,honsiorovskyi/go,constantine001/go,dpatel06/go,qskycolor/go,jacobxk/go,alex-zhang/go,joshsammut/go,xujianhai/go,g522342435/go,odeke-em/go,dafyddcrosby/go,odeke-em/go,Badredapple/go,danycoro/go,polyverse-security/go,skotti/go,vishsingh/go,cyberroadie/go,jonahglover/go,vsekhar/elastic-go,malvira/go,CAFxX/go,goodlang/good,likesea/go,jacobsa/go,jonahglover/go,codestation/go,CAFxX/go,binarycrusader/go,undergrowthlinear/go,vishsingh/go,xiuzhifu/go,zcwfeng/go,beealone/go,skatsuta/go,Jordanzuo/go,nakedgc/go,jasonxiong/go,kevinc0825/go,vanloswang/go,theif519/go,mdp/go,vanloswang/go,cyberroadie/go,kevinc0825/go,odeke-em/go,kim-racktop/go,xujianhai/go,mikekap/go,gdey/go,vanloswang/go,NunoEdgarGub1/go,arschles/golang-go,sosop/go,jdhenke/go,skatsuta/go,stormltf/go,yasarkunduz/go,Pulgafree/go,mwhudson/go,gohin/go,CiscoCloud/go,fjballest/golang,xiaobodu/go,springning/go,vsdutka/go,CiscoCloud/go,josharian/go,ErikDubbelboer/go,josharian/go,jdhenke/go,goodlang/good,yangzhongj/go,andrewchambers/go,stormltf/go,linux-on-ibm-z/go,zhangg/go,honsiorovskyi/go,devpadawan/go,dgnorton/go,arschles/golang-go,yangzhongj/go,Pulgafree/go,xujianhai/go,dgnorton/go,famorted/go,sinuos/go,beealone/go,jdhenke/go,Samurais/go,chinanjjohn2012/go,leeric92/go,uileyar/go,mbrukman/go,codestation/go,NunoEdgarGub1/go,mgyenik/go,uileyar/go,jonasi/go,ImJasonH/go,zouchao2010/go,odeke-em/go,jonasi/go,xiaobodu/go,theif519/go,xujianhai/go,mwhudson/go,cainiaocome/go,Stan-Lin-/go,GeorgiCodes/go,jacobxk/go,dafyddcrosby/go,jonathanmarvens/go,youprofit/go,vsdutka/go,Charlesdong/go-1,jdhenke/go,mikekap/go,b54898533/go,CodyGuo/go,nakedgc/go,undergrowthlinear/go,jacobxk/go,xiuzhifu/go,yasarkunduz/go,sinuos/go,fjballest/golang,derekmarcotte/go,RBEGamer/go,vishsingh/go,willjunspecial/go,arschles/go-1,beealone/go,golang/go,nakedgc/go,chinanjjohn2012/go,JioCloud/go,NichoZhang/go,roth1002/go,Endika/go,skatsuta/go,Jordanzuo/go,sinuos/go,Charlesdong/go-1,jdeng/go,zhangg/go,kim-racktop/go,skotti/go,cyberroadie/go,miolini/go,zcwfeng/go,deft-code/go,jacobsa/go,alex-zhang/go,zouchao2010/go,theass/go,skatsuta/go,josharian/go,derekmarcotte/go,polyverse-security/go,yasarkunduz/go,mwhudson/go,alash3al/go,ObjectiveJoe/go,malvira/go,ObjectiveJoe/go,yuhengye/go,youprofit/go,myPublicGit/go,jonahglover/go,beealone/go,golang/go,RBEGamer/go,binarycrusader/go,jefby/go,jacobhaven/go,yasarkunduz/go,ichu501/go,kim-racktop/go,xiaobodu/go,xujianhai/go,undergrowthlinear/go,cloudrain21/go,albertjin/golang-go,dterei/go,sndnvaps/go,polyverse-security/go,ErikDubbelboer/go,sosop/go,ErikDubbelboer/go,ganboing/go-esx,xinhuang327/go,pgmreddy/go,andrewchambers/go,linux-on-ibm-z/go,dgnorton/go,gdey/go,JioCloud/go,famorted/go,cnbin/go,greyhwndz/go,cloudrain21/go,kevinc0825/go,undergrowthlinear/go,yuhengye/go,roth1002/go,cloudrain21/go,cnbin/go,uileyar/go,akutz/go,jdeng/go,jonasi/go,Endika/go,roth1002/go,mdp/go,vanloswang/go,Pulgafree/go,shines77/go,golang/go,Endika/go,Charlesdong/go-1,jonathanmarvens/go,greyhwndz/go,JioCloud/go,famorted/go,skatsuta/go,suncycheng/go,zouchao2010/go,binarycrusader/go,rentongzhang/go,Pulgafree/go,theass/go,b54898533/go,AALEKH/go,xinhuang327/go,nakedgc/go,famorted/go,Samurais/go,AALEKH/go,pgmreddy/go,roth1002/go,xiaobodu/go,4ad/go,beealone/go,roth1002/go,xiuzhifu/go,g522342435/go