cmd/go: Skip note reading test with linkmode external on openbsd/arm
cmd/go: Skip note reading test with linkmode external on openbsd/arm

openbsd/arm does not support external linking - skip the note reading test that
uses linkmode external on this platform. While here, cleanup the code and
consistently use t.Skipf for all platforms that cannot run this test.

Change-Id: I64f0d9e038bc4c993c3d843fc069a0b723a924d6
Reviewed-on: https://go-review.googlesource.com/15054
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

suncycheng/go,alex-zhang/go,Jordanzuo/go,momchil-velikov/go,CAFxX/go,CAFxX/go,beealone/go,odeke-em/go,mwhudson/go,rachtsingh/gogojuice,miolini/go,cloudflare/go,akutz/go,vanloswang/go,akutz/go,vsekhar/elastic-go,likesea/go,goodlang/good,theif519/go,likesea/go,malvira/go,codestation/go,miolini/go,theif519/go,goodlang/good,polyverse-security/go,rachtsingh/gogojuice,Cofyc/go,Endika/go,vsekhar/elastic-go,gdey/go,golang/go,binarycrusader/go,jonasi/go,cyberroadie/go,golang/go,suncycheng/go,CAFxX/go,binarycrusader/go,malvira/go,likesea/go,suncycheng/go,dterei/go,likesea/go,gdey/go,rachtsingh/gogojuice,momchil-velikov/go,cloudflare/go,theif519/go,fjballest/golang,jacobsa/go,Jordanzuo/go,cloudflare/go,josharian/go,roth1002/go,malvira/go,derekmarcotte/go,kim-racktop/go,theif519/go,deft-code/go,golang/go,golang/go,Endika/go,yasarkunduz/go,momchil-velikov/go,sndnvaps/go,ImJasonH/go,Jordanzuo/go,cloudflare/go,binarycrusader/go,miolini/go,Cofyc/go,likesea/go,akutz/go,polyverse-security/go,jonasi/go,sndnvaps/go,gdey/go,vanloswang/go,fjballest/golang,momchil-velikov/go,christopher-henderson/Go,fjballest/golang,jonasi/go,codestation/go,ImJasonH/go,akutz/go,Cofyc/go,nawawi/go,kim-racktop/go,rachtsingh/gogojuice,derekmarcotte/go,goodlang/good,polyverse-security/go,ImJasonH/go,jonasi/go,roth1002/go,odeke-em/go,rachtsingh/gogojuice,derekmarcotte/go,binarycrusader/go,miolini/go,beealone/go,gdey/go,polyverse-security/go,jacobsa/go,CAFxX/go,akutz/go,ImJasonH/go,derekmarcotte/go,polyverse-security/go,golang/go,alex-zhang/go,fjballest/golang,dterei/go,codestation/go,dterei/go,Endika/go,binarycrusader/go,linux-on-ibm-z/go,yasarkunduz/go,miolini/go,CAFxX/go,linux-on-ibm-z/go,nawawi/go,ganboing/go-esx,kim-racktop/go,4ad/go,4ad/go,binarycrusader/go,Cofyc/go,roth1002/go,josharian/go,ganboing/go-esx,ganboing/go-esx,josharian/go,mwhudson/go,linux-on-ibm-z/go,cyberroadie/go,linux-on-ibm-z/go,vanloswang/go,dterei/go,roth1002/go,yasarkunduz/go,suncycheng/go,CAFxX/go,nawawi/go,suncycheng/go,theif519/go,yasarkunduz/go,goodlang/good,josharian/go,Jordanzuo/go,codestation/go,dterei/go,polyverse-security/go,sndnvaps/go,theif519/go,roth1002/go,vsekhar/elastic-go,jacobsa/go,derekmarcotte/go,gdey/go,josharian/go,nawawi/go,suncycheng/go,jacobsa/go,jacobsa/go,deft-code/go,josharian/go,kim-racktop/go,likesea/go,goodlang/good,ganboing/go-esx,4ad/go,goodlang/good,Cofyc/go,alex-zhang/go,roth1002/go,alex-zhang/go,alex-zhang/go,4ad/go,odeke-em/go,Samurais/go,codestation/go,beealone/go,ganboing/go-esx,ImJasonH/go,CAFxX/go,vsekhar/elastic-go,jacobsa/go,nawawi/go,fjballest/golang,akutz/go,gdey/go,jonasi/go,cyberroadie/go,4ad/go,ImJasonH/go,codestation/go,Samurais/go,vanloswang/go,miolini/go,linux-on-ibm-z/go,yasarkunduz/go,mwhudson/go,fjballest/golang,malvira/go,mwhudson/go,Samurais/go,roth1002/go,kim-racktop/go,theif519/go,CAFxX/go,alex-zhang/go,cloudflare/go,akutz/go,Endika/go,mwhudson/go,goodlang/good,odeke-em/go,beealone/go,malvira/go,odeke-em/go,fjballest/golang,dterei/go,deft-code/go,Endika/go,Endika/go,sndnvaps/go,Samurais/go,gdey/go,polyverse-security/go,Jordanzuo/go,likesea/go,4ad/go,rachtsingh/gogojuice,yasarkunduz/go,vsekhar/elastic-go,Cofyc/go,cloudflare/go,Endika/go,kim-racktop/go,ImJasonH/go,malvira/go,yasarkunduz/go,jonasi/go,nawawi/go,binarycrusader/go,linux-on-ibm-z/go,ganboing/go-esx,kim-racktop/go,deft-code/go,josharian/go,jacobsa/go,cyberroadie/go,deft-code/go,deft-code/go,dterei/go,Jordanzuo/go,nawawi/go,ganboing/go-esx,linux-on-ibm-z/go,mwhudson/go,alex-zhang/go,odeke-em/go,cyberroadie/go,jacobsa/go,vanloswang/go,deft-code/go,suncycheng/go,miolini/go,Jordanzuo/go,alex-zhang/go,roth1002/go,Samurais/go,vsekhar/elastic-go,beealone/go,beealone/go,binarycrusader/go,mwhudson/go,sndnvaps/go,goodlang/good,derekmarcotte/go,derekmarcotte/go,linux-on-ibm-z/go,ImJasonH/go,cloudflare/go,rachtsingh/gogojuice,vanloswang/go,odeke-em/go,Endika/go,sndnvaps/go,Samurais/go,yasarkunduz/go,codestation/go,momchil-velikov/go,golang/go,jonasi/go,gdey/go,Samurais/go,golang/go,malvira/go,Cofyc/go,dterei/go,beealone/go,4ad/go,theif519/go,josharian/go,suncycheng/go,Samurais/go,jonasi/go,momchil-velikov/go,codestation/go,cloudflare/go,sndnvaps/go,cyberroadie/go,rachtsingh/gogojuice,deft-code/go,malvira/go,fjballest/golang,ganboing/go-esx,polyverse-security/go,miolini/go,cyberroadie/go,vsekhar/elastic-go,sndnvaps/go,likesea/go,akutz/go,cyberroadie/go,mwhudson/go,derekmarcotte/go,Jordanzuo/go,vanloswang/go,kim-racktop/go,vsekhar/elastic-go,vanloswang/go,nawawi/go,Cofyc/go,odeke-em/go,golang/go,momchil-velikov/go,momchil-velikov/go,beealone/go,4ad/go