Remove use of Encoding.Default
Remove use of Encoding.Default

This API doesn't exist in CoreFx.  It was used in EncodedStringText as
the last ditch effort for string decoding.  Switched to explicitly use
codepage 1252 as the last ditch encoding effort.

closes #1623

zooba/roslyn,Giftednewt/roslyn,budcribar/roslyn,sharadagrawal/Roslyn,chenxizhang/roslyn,kienct89/roslyn,enginekit/roslyn,srivatsn/roslyn,VSadov/roslyn,mattscheffer/roslyn,pjmagee/roslyn,MavenRain/roslyn,srivatsn/roslyn,managed-commons/roslyn,doconnell565/roslyn,kuhlenh/roslyn,tmeschter/roslyn,genlu/roslyn,tmat/roslyn,Giten2004/roslyn,managed-commons/roslyn,ljw1004/roslyn,russpowers/roslyn,VShangxiao/roslyn,rgani/roslyn,Pvlerick/roslyn,moozzyk/roslyn,lorcanmooney/roslyn,tannergooding/roslyn,ilyes14/roslyn,evilc0des/roslyn,swaroop-sridhar/roslyn,AlexisArce/roslyn,khyperia/roslyn,chenxizhang/roslyn,kelltrick/roslyn,AnthonyDGreen/roslyn,huoxudong125/roslyn,KevinRansom/roslyn,natgla/roslyn,paulvanbrenk/roslyn,pdelvo/roslyn,v-codeel/roslyn,tvand7093/roslyn,jbhensley/roslyn,FICTURE7/roslyn,bbarry/roslyn,a-ctor/roslyn,Hosch250/roslyn,diryboy/roslyn,ericfe-ms/roslyn,CyrusNajmabadi/roslyn,AlekseyTs/roslyn,jmarolf/roslyn,danielcweber/roslyn,bbarry/roslyn,agocke/roslyn,3F/roslyn,RipCurrent/roslyn,yjfxfjch/roslyn,panopticoncentral/roslyn,pjmagee/roslyn,KevinRansom/roslyn,huoxudong125/roslyn,eriawan/roslyn,FICTURE7/roslyn,khyperia/roslyn,balajikris/roslyn,BugraC/roslyn,managed-commons/roslyn,v-codeel/roslyn,drognanar/roslyn,vslsnap/roslyn,heejaechang/roslyn,AlexisArce/roslyn,jamesqo/roslyn,mgoertz-msft/roslyn,cston/roslyn,yeaicc/roslyn,antonssonj/roslyn,diryboy/roslyn,kuhlenh/roslyn,jhendrixMSFT/roslyn,grianggrai/roslyn,kelltrick/roslyn,FICTURE7/roslyn,paladique/roslyn,KevinRansom/roslyn,davkean/roslyn,sharadagrawal/Roslyn,stephentoub/roslyn,Pvlerick/roslyn,reaction1989/roslyn,khyperia/roslyn,nagyistoce/roslyn,mattscheffer/roslyn,BugraC/roslyn,MihaMarkic/roslyn-prank,oocx/roslyn,GuilhermeSa/roslyn,Maxwe11/roslyn,supriyantomaftuh/roslyn,drognanar/roslyn,mmitche/roslyn,vcsjones/roslyn,brettfo/roslyn,TyOverby/roslyn,taylorjonl/roslyn,thomaslevesque/roslyn,jasonmalinowski/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,ValentinRueda/roslyn,pdelvo/roslyn,amcasey/roslyn,gafter/roslyn,RipCurrent/roslyn,AnthonyDGreen/roslyn,droyad/roslyn,khellang/roslyn,danielcweber/roslyn,abock/roslyn,AmadeusW/roslyn,lorcanmooney/roslyn,MihaMarkic/roslyn-prank,VShangxiao/roslyn,droyad/roslyn,panopticoncentral/roslyn,tmeschter/roslyn,stebet/roslyn,reaction1989/roslyn,weltkante/roslyn,Shiney/roslyn,AArnott/roslyn,antonssonj/roslyn,mattwar/roslyn,bkoelman/roslyn,KevinH-MS/roslyn,poizan42/roslyn,rgani/roslyn,stjeong/roslyn,lisong521/roslyn,thomaslevesque/roslyn,weltkante/roslyn,basoundr/roslyn,tsdl2013/roslyn,stebet/roslyn,aelij/roslyn,mattwar/roslyn,REALTOBIZ/roslyn,paulvanbrenk/roslyn,leppie/roslyn,robinsedlaczek/roslyn,moozzyk/roslyn,DinoV/roslyn,aanshibudhiraja/Roslyn,AlekseyTs/roslyn,stephentoub/roslyn,v-codeel/roslyn,orthoxerox/roslyn,orthoxerox/roslyn,davkean/roslyn,jaredpar/roslyn,sharwell/roslyn,dpoeschl/roslyn,xasx/roslyn,rchande/roslyn,zmaruo/roslyn,jamesqo/roslyn,davkean/roslyn,OmniSharp/roslyn,sharadagrawal/Roslyn,magicbing/roslyn,a-ctor/roslyn,akrisiun/roslyn,kelltrick/roslyn,dpoeschl/roslyn,oberxon/roslyn,jasonmalinowski/roslyn,jmarolf/roslyn,rgani/roslyn,bkoelman/roslyn,nguerrera/roslyn,nguerrera/roslyn,antiufo/roslyn,Giftednewt/roslyn,jonatassaraiva/roslyn,AArnott/roslyn,DustinCampbell/roslyn,zmaruo/roslyn,lorcanmooney/roslyn,nguerrera/roslyn,jasonmalinowski/roslyn,tsdl2013/roslyn,kienct89/roslyn,stjeong/roslyn,zooba/roslyn,michalhosala/roslyn,cston/roslyn,dotnet/roslyn,diryboy/roslyn,magicbing/roslyn,jroggeman/roslyn,jkotas/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,AlekseyTs/roslyn,KiloBravoLima/roslyn,enginekit/roslyn,mseamari/Stuff,genlu/roslyn,kienct89/roslyn,YOTOV-LIMITED/roslyn,ilyes14/roslyn,AmadeusW/roslyn,ljw1004/roslyn,grianggrai/roslyn,michalhosala/roslyn,CaptainHayashi/roslyn,budcribar/roslyn,EricArndt/roslyn,KirillOsenkov/roslyn,Giten2004/roslyn,wvdd007/roslyn,jeremymeng/roslyn,xoofx/roslyn,3F/roslyn,dpen2000/roslyn,wvdd007/roslyn,MichalStrehovsky/roslyn,jrharmon/roslyn,amcasey/roslyn,srivatsn/roslyn,jroggeman/roslyn,robinsedlaczek/roslyn,krishnarajbb/roslyn,paladique/roslyn,dotnet/roslyn,mseamari/Stuff,jaredpar/roslyn,natidea/roslyn,MattWindsor91/roslyn,JakeGinnivan/roslyn,KiloBravoLima/roslyn,MatthieuMEZIL/roslyn,VPashkov/roslyn,AlexisArce/roslyn,KashishArora/Roslyn,weltkante/roslyn,aanshibudhiraja/Roslyn,dsplaisted/roslyn,Hosch250/roslyn,pjmagee/roslyn,dsplaisted/roslyn,jeremymeng/roslyn,marksantos/roslyn,natidea/roslyn,SeriaWei/roslyn,jcouv/roslyn,jkotas/roslyn,grianggrai/roslyn,basoundr/roslyn,GuilhermeSa/roslyn,HellBrick/roslyn,shyamnamboodiripad/roslyn,YOTOV-LIMITED/roslyn,poizan42/roslyn,droyad/roslyn,ahmedshuhel/roslyn,jeremymeng/roslyn,krishnarajbb/roslyn,Shiney/roslyn,tang7526/roslyn,jaredpar/roslyn,MattWindsor91/roslyn,danielcweber/roslyn,oberxon/roslyn,RipCurrent/roslyn,MatthieuMEZIL/roslyn,ericfe-ms/roslyn,jcouv/roslyn,taylorjonl/roslyn,thomaslevesque/roslyn,ValentinRueda/roslyn,xasx/roslyn,rchande/roslyn,furesoft/roslyn,nagyistoce/roslyn,lisong521/roslyn,mmitche/roslyn,basoundr/roslyn,eriawan/roslyn,mmitche/roslyn,dovzhikova/roslyn,jrharmon/roslyn,VitalyTVA/roslyn,dovzhikova/roslyn,Shiney/roslyn,ErikSchierboom/roslyn,Pvlerick/roslyn,VSadov/roslyn,vslsnap/roslyn,brettfo/roslyn,furesoft/roslyn,VPashkov/roslyn,dpen2000/roslyn,doconnell565/roslyn,abock/roslyn,tvand7093/roslyn,shyamnamboodiripad/roslyn,poizan42/roslyn,hanu412/roslyn,supriyantomaftuh/roslyn,YOTOV-LIMITED/roslyn,a-ctor/roslyn,robinsedlaczek/roslyn,paulvanbrenk/roslyn,russpowers/roslyn,DanielRosenwasser/roslyn,xoofx/roslyn,nemec/roslyn,ahmedshuhel/roslyn,mgoertz-msft/roslyn,bartdesmet/roslyn,oberxon/roslyn,amcasey/roslyn,devharis/roslyn,yjfxfjch/roslyn,garryforreg/roslyn,EricArndt/roslyn,tvand7093/roslyn,Giten2004/roslyn,tmeschter/roslyn,nemec/roslyn,AArnott/roslyn,AnthonyDGreen/roslyn,Maxwe11/roslyn,dotnet/roslyn,mseamari/Stuff,DanielRosenwasser/roslyn,jbhensley/roslyn,balajikris/roslyn,oocx/roslyn,gafter/roslyn,wvdd007/roslyn,KiloBravoLima/roslyn,HellBrick/roslyn,garryforreg/roslyn,supriyantomaftuh/roslyn,evilc0des/roslyn,KevinH-MS/roslyn,dpoeschl/roslyn,dovzhikova/roslyn,cybernet14/roslyn,tmat/roslyn,VitalyTVA/roslyn,cybernet14/roslyn,tmat/roslyn,chenxizhang/roslyn,ericfe-ms/roslyn,rchande/roslyn,MavenRain/roslyn,Hosch250/roslyn,KirillOsenkov/roslyn,Inverness/roslyn,genlu/roslyn,REALTOBIZ/roslyn,zmaruo/roslyn,hanu412/roslyn,yjfxfjch/roslyn,CaptainHayashi/roslyn,furesoft/roslyn,jeffanders/roslyn,tang7526/roslyn,heejaechang/roslyn,mattscheffer/roslyn,ljw1004/roslyn,stephentoub/roslyn,MichalStrehovsky/roslyn,DinoV/roslyn,shyamnamboodiripad/roslyn,jbhensley/roslyn,vcsjones/roslyn,ErikSchierboom/roslyn,bkoelman/roslyn,tannergooding/roslyn,abock/roslyn,yeaicc/roslyn,bartdesmet/roslyn,stebet/roslyn,KamalRathnayake/roslyn,aanshibudhiraja/Roslyn,SeriaWei/roslyn,sharwell/roslyn,taylorjonl/roslyn,orthoxerox/roslyn,heejaechang/roslyn,michalhosala/roslyn,bartdesmet/roslyn,VitalyTVA/roslyn,MichalStrehovsky/roslyn,jonatassaraiva/roslyn,Inverness/roslyn,mirhagk/roslyn,marksantos/roslyn,eriawan/roslyn,leppie/roslyn,KamalRathnayake/roslyn,ValentinRueda/roslyn,TyOverby/roslyn,jrharmon/roslyn,jeffanders/roslyn,antiufo/roslyn,vslsnap/roslyn,xasx/roslyn,jmarolf/roslyn,khellang/roslyn,paladique/roslyn,CyrusNajmabadi/roslyn,VShangxiao/roslyn,ErikSchierboom/roslyn,KamalRathnayake/roslyn,xoofx/roslyn,OmniSharp/roslyn,KevinH-MS/roslyn,cybernet14/roslyn,antonssonj/roslyn,krishnarajbb/roslyn,DinoV/roslyn,EricArndt/roslyn,akrisiun/roslyn,agocke/roslyn,physhi/roslyn,MattWindsor91/roslyn,agocke/roslyn,stjeong/roslyn,jhendrixMSFT/roslyn,TyOverby/roslyn,swaroop-sridhar/roslyn,marksantos/roslyn,hanu412/roslyn,cston/roslyn,khellang/roslyn,bbarry/roslyn,magicbing/roslyn,balajikris/roslyn,tannergooding/roslyn,gafter/roslyn,natidea/roslyn,DustinCampbell/roslyn,jroggeman/roslyn,SeriaWei/roslyn,vcsjones/roslyn,akrisiun/roslyn,mgoertz-msft/roslyn,oocx/roslyn,mavasani/roslyn,kuhlenh/roslyn,ilyes14/roslyn,VPashkov/roslyn,OmarTawfik/roslyn,aelij/roslyn,nemec/roslyn,MattWindsor91/roslyn,MavenRain/roslyn,OmarTawfik/roslyn,russpowers/roslyn,panopticoncentral/roslyn,MatthieuMEZIL/roslyn,mavasani/roslyn,KashishArora/Roslyn,physhi/roslyn,dsplaisted/roslyn,MihaMarkic/roslyn-prank,nagyistoce/roslyn,brettfo/roslyn,physhi/roslyn,AdamSpeight2008/roslyn-AdamSpeight2008,budcribar/roslyn,REALTOBIZ/roslyn,antiufo/roslyn,jamesqo/roslyn,aelij/roslyn,DanielRosenwasser/roslyn,jcouv/roslyn,doconnell565/roslyn,reaction1989/roslyn,BugraC/roslyn,jeffanders/roslyn,huoxudong125/roslyn,enginekit/roslyn,sharadagrawal/TestProject2,VSadov/roslyn,AmadeusW/roslyn,OmniSharp/roslyn,tsdl2013/roslyn,natgla/roslyn,zooba/roslyn,garryforreg/roslyn,evilc0des/roslyn,moozzyk/roslyn,Maxwe11/roslyn,KirillOsenkov/roslyn,jhendrixMSFT/roslyn,jonatassaraiva/roslyn,JakeGinnivan/roslyn,CaptainHayashi/roslyn,OmarTawfik/roslyn,ahmedshuhel/roslyn,Giftednewt/roslyn,3F/roslyn,mirhagk/roslyn,jkotas/roslyn,GuilhermeSa/roslyn,CyrusNajmabadi/roslyn,yeaicc/roslyn,mirhagk/roslyn,sharwell/roslyn,JakeGinnivan/roslyn,DustinCampbell/roslyn,HellBrick/roslyn,mattwar/roslyn,leppie/roslyn,lisong521/roslyn,devharis/roslyn,pdelvo/roslyn,dpen2000/roslyn,tang7526/roslyn,devharis/roslyn,sharadagrawal/TestProject2,natgla/roslyn,drognanar/roslyn,mavasani/roslyn,swaroop-sridhar/roslyn,KashishArora/Roslyn,sharadagrawal/TestProject2,Inverness/roslyn