Fix unwinding past main on OSX
Fix unwinding past main on OSX

When reaching the bottom of the real stack, OSX does not change the $pc
to 0x0, like llvm libunwind.  It returns 0 from unw_step, and leaves the
$pc unchanged, so we will track cur and prev pc and guard for this as well
Fixes Localloc codegen test, and also verified a simple throw from main
works as expected.

Djuffin/coreclr,Alcaro/coreclr,ytechie/coreclr,GuilhermeSa/coreclr,ZhichengZhu/coreclr,naamunds/coreclr,libengu/coreclr,AlexGhiondea/coreclr,matthubin/coreclr,ktos/coreclr,gitchomik/coreclr,JonHanna/coreclr,MCGPPeters/coreclr,sjsinju/coreclr,apanda/coreclr,JonHanna/coreclr,bartonjs/coreclr,bartonjs/coreclr,taylorjonl/coreclr,bitcrazed/coreclr,grokys/coreclr,stormleoxia/coreclr,david-mitchell/coreclr,geertdoornbos/coreclr,parjong/coreclr,xoofx/coreclr,fffej/coreclr,hseok-oh/coreclr,bitcrazed/coreclr,qiudesong/coreclr,DickvdBrink/coreclr,alexperovich/coreclr,AlfredoMS/coreclr,perfectphase/coreclr,libengu/coreclr,sperling/coreclr,stormleoxia/coreclr,krytarowski/coreclr,iamjasonp/coreclr,bartonjs/coreclr,DasAllFolks/coreclr,jhendrixMSFT/coreclr,krixalis/coreclr,LLITCHEV/coreclr,taylorjonl/coreclr,JosephTremoulet/coreclr,SlavaRa/coreclr,andschwa/coreclr,DasAllFolks/coreclr,fernando-rodriguez/coreclr,DickvdBrink/coreclr,serenabenny/coreclr,bartdesmet/coreclr,sagood/coreclr,chenxizhang/coreclr,Alcaro/coreclr,bitcrazed/coreclr,Dmitry-Me/coreclr,kyulee1/coreclr,sejongoh/coreclr,alexperovich/coreclr,dasMulli/coreclr,Lucrecious/coreclr,neurospeech/coreclr,richardlford/coreclr,manu-silicon/coreclr,gkhanna79/coreclr,shana/coreclr,hanu412/coreclr,DickvdBrink/coreclr,dkorolev/coreclr,dkorolev/coreclr,Djuffin/coreclr,xtypebee/coreclr,mmitche/coreclr,blackdwarf/coreclr,xtypebee/coreclr,serenabenny/coreclr,mmitche/coreclr,YongseopKim/coreclr,benpye/coreclr,Sridhar-MS/coreclr,LLITCHEV/coreclr,benpye/coreclr,krytarowski/coreclr,Dmitry-Me/coreclr,wkchoy74/coreclr,bjjones/coreclr,jhendrixMSFT/coreclr,Godin/coreclr,SlavaRa/coreclr,jakesays/coreclr,matthubin/coreclr,yizhang82/coreclr,ericeil/coreclr,swgillespie/coreclr,zmaruo/coreclr,DickvdBrink/coreclr,mocsy/coreclr,chaos7theory/coreclr,bitcrazed/coreclr,Lucrecious/coreclr,iamjasonp/coreclr,blackdwarf/coreclr,mocsy/coreclr,tijoytom/coreclr,misterzik/coreclr,chaos7theory/coreclr,cmckinsey/coreclr,taylorjonl/coreclr,vinnyrom/coreclr,swgillespie/coreclr,libengu/coreclr,sergey-raevskiy/coreclr,shana/coreclr,hseok-oh/coreclr,GuilhermeSa/coreclr,cmckinsey/coreclr,chrishaly/coreclr,david-mitchell/coreclr,zmaruo/coreclr,mokchhya/coreclr,SpotLabsNET/coreclr,schellap/coreclr,gkhanna79/coreclr,AlexGhiondea/coreclr,sejongoh/coreclr,david-mitchell/coreclr,mskvortsov/coreclr,bartonjs/coreclr,jakesays/coreclr,sjsinju/coreclr,sergey-raevskiy/coreclr,YongseopKim/coreclr,misterzik/coreclr,AlfredoMS/coreclr,krixalis/coreclr,Samana/coreclr,spoiledsport/coreclr,ktos/coreclr,bartdesmet/coreclr,botaberg/coreclr,benpye/coreclr,Sridhar-MS/coreclr,parjong/coreclr,fernando-rodriguez/coreclr,gitchomik/coreclr,Alcaro/coreclr,andschwa/coreclr,poizan42/coreclr,Djuffin/coreclr,orthoxerox/coreclr,russellhadley/coreclr,botaberg/coreclr,zmaruo/coreclr,swgillespie/coreclr,manu-silicon/coreclr,xtypebee/coreclr,ytechie/coreclr,martinwoodward/coreclr,JonHanna/coreclr,andschwa/coreclr,Dmitry-Me/coreclr,richardlford/coreclr,chaos7theory/coreclr,Alcaro/coreclr,sejongoh/coreclr,geertdoornbos/coreclr,dasMulli/coreclr,ganeshran/coreclr,MCGPPeters/coreclr,mokchhya/coreclr,mocsy/coreclr,ericeil/coreclr,martinwoodward/coreclr,fieryorc/coreclr,chrishaly/coreclr,mocsy/coreclr,geertdoornbos/coreclr,sejongoh/coreclr,dkorolev/coreclr,iamjasonp/coreclr,bitcrazed/coreclr,naamunds/coreclr,xtypebee/coreclr,misterzik/coreclr,botaberg/coreclr,hanu412/coreclr,ytechie/coreclr,cshung/coreclr,James-Ko/coreclr,dpodder/coreclr,ericeil/coreclr,serenabenny/coreclr,dkorolev/coreclr,misterzik/coreclr,apanda/coreclr,josteink/coreclr,xtypebee/coreclr,wkchoy74/coreclr,rartemev/coreclr,SlavaRa/coreclr,sejongoh/coreclr,ericeil/coreclr,grokys/coreclr,ruben-ayrapetyan/coreclr,swgillespie/coreclr,MCGPPeters/coreclr,Djuffin/coreclr,dkorolev/coreclr,chuck-mitchell/coreclr,yeaicc/coreclr,sagood/coreclr,JosephTremoulet/coreclr,chrishaly/coreclr,schellap/coreclr,libengu/coreclr,andschwa/coreclr,Sridhar-MS/coreclr,wkchoy74/coreclr,fieryorc/coreclr,fffej/coreclr,wateret/coreclr,josteink/coreclr,martinwoodward/coreclr,yizhang82/coreclr,ktos/coreclr,wtgodbe/coreclr,matthubin/coreclr,lzcj4/coreclr,gitchomik/coreclr,andschwa/coreclr,josteink/coreclr,DasAllFolks/coreclr,lzcj4/coreclr,sperling/coreclr,xoofx/coreclr,wtgodbe/coreclr,fffej/coreclr,pgavlin/coreclr,MCGPPeters/coreclr,kyulee1/coreclr,sergey-raevskiy/coreclr,roncain/coreclr,ruben-ayrapetyan/coreclr,benpye/coreclr,martinwoodward/coreclr,stormleoxia/coreclr,mskvortsov/coreclr,taylorjonl/coreclr,bartonjs/coreclr,LLITCHEV/coreclr,serenabenny/coreclr,chuck-mitchell/coreclr,Samana/coreclr,OryJuVog/coreclr,mocsy/coreclr,blackdwarf/coreclr,yizhang82/coreclr,russellhadley/coreclr,orthoxerox/coreclr,Samana/coreclr,cshung/coreclr,apanda/coreclr,Dmitry-Me/coreclr,sagood/coreclr,bjjones/coreclr,krytarowski/coreclr,naamunds/coreclr,ruben-ayrapetyan/coreclr,sjsinju/coreclr,chrishaly/coreclr,wateret/coreclr,perfectphase/coreclr,krytarowski/coreclr,sergey-raevskiy/coreclr,Godin/coreclr,russellhadley/coreclr,fieryorc/coreclr,perfectphase/coreclr,bartdesmet/coreclr,sagood/coreclr,sperling/coreclr,serenabenny/coreclr,grokys/coreclr,ragmani/coreclr,vinnyrom/coreclr,shana/coreclr,dkorolev/coreclr,poizan42/coreclr,botaberg/coreclr,chuck-mitchell/coreclr,ytechie/coreclr,spoiledsport/coreclr,grokys/coreclr,lzcj4/coreclr,KrzysztofCwalina/coreclr,sperling/coreclr,cshung/coreclr,xoofx/coreclr,sjsinju/coreclr,yeaicc/coreclr,OryJuVog/coreclr,krytarowski/coreclr,sperling/coreclr,poizan42/coreclr,rartemev/coreclr,ZhichengZhu/coreclr,yeaicc/coreclr,ktos/coreclr,wateret/coreclr,lzcj4/coreclr,mskvortsov/coreclr,manu-silicon/coreclr,manu-silicon/coreclr,matthubin/coreclr,cydhaselton/coreclr,benpye/coreclr,wtgodbe/coreclr,tijoytom/coreclr,apanda/coreclr,neurospeech/coreclr,jhendrixMSFT/coreclr,bjjones/coreclr,roncain/coreclr,yeaicc/coreclr,ganeshran/coreclr,taylorjonl/coreclr,kyulee1/coreclr,YongseopKim/coreclr,jamesqo/coreclr,roncain/coreclr,shahid-pk/coreclr,Dmitry-Me/coreclr,rartemev/coreclr,ragmani/coreclr,ruben-ayrapetyan/coreclr,libengu/coreclr,krk/coreclr,tijoytom/coreclr,shahid-pk/coreclr,stormleoxia/coreclr,LLITCHEV/coreclr,chrishaly/coreclr,perfectphase/coreclr,kyulee1/coreclr,jamesqo/coreclr,shahid-pk/coreclr,chuck-mitchell/coreclr,josteink/coreclr,mokchhya/coreclr,dasMulli/coreclr,DickvdBrink/coreclr,sperling/coreclr,shana/coreclr,fieryorc/coreclr,spoiledsport/coreclr,yeaicc/coreclr,shana/coreclr,botaberg/coreclr,ragmani/coreclr,bartdesmet/coreclr,jamesqo/coreclr,KrzysztofCwalina/coreclr,tijoytom/coreclr,krytarowski/coreclr,dpodder/coreclr,cmckinsey/coreclr,cshung/coreclr,Dmitry-Me/coreclr,rartemev/coreclr,ganeshran/coreclr,YongseopKim/coreclr,yizhang82/coreclr,bjjones/coreclr,AlfredoMS/coreclr,yizhang82/coreclr,dpodder/coreclr,JosephTremoulet/coreclr,david-mitchell/coreclr,sjsinju/coreclr,xoofx/coreclr,manu-silicon/coreclr,vinnyrom/coreclr,wtgodbe/coreclr,pgavlin/coreclr,blackdwarf/coreclr,bartonjs/coreclr,krk/coreclr,richardlford/coreclr,schellap/coreclr,gitchomik/coreclr,chuck-mitchell/coreclr,Lucrecious/coreclr,KrzysztofCwalina/coreclr,ZhichengZhu/coreclr,vinnyrom/coreclr,chenxizhang/coreclr,krk/coreclr,dasMulli/coreclr,gkhanna79/coreclr,James-Ko/coreclr,GuilhermeSa/coreclr,mskvortsov/coreclr,YongseopKim/coreclr,krk/coreclr,apanda/coreclr,roncain/coreclr,hanu412/coreclr,sejongoh/coreclr,tijoytom/coreclr,cmckinsey/coreclr,poizan42/coreclr,schellap/coreclr,martinwoodward/coreclr,ytechie/coreclr,dasMulli/coreclr,yeaicc/coreclr,gkhanna79/coreclr,schellap/coreclr,bitcrazed/coreclr,stormleoxia/coreclr,mmitche/coreclr,wkchoy74/coreclr,jamesqo/coreclr,vinnyrom/coreclr,dpodder/coreclr,apanda/coreclr,SpotLabsNET/coreclr,dasMulli/coreclr,ZhichengZhu/coreclr,bjjones/coreclr,roncain/coreclr,parjong/coreclr,ragmani/coreclr,Alcaro/coreclr,Samana/coreclr,chenxizhang/coreclr,geertdoornbos/coreclr,fernando-rodriguez/coreclr,cydhaselton/coreclr,MCGPPeters/coreclr,fernando-rodriguez/coreclr,perfectphase/coreclr,david-mitchell/coreclr,bartdesmet/coreclr,taylorjonl/coreclr,ZhichengZhu/coreclr,JonHanna/coreclr,krixalis/coreclr,bartonjs/coreclr,orthoxerox/coreclr,jamesqo/coreclr,DasAllFolks/coreclr,mokchhya/coreclr,richardlford/coreclr,JosephTremoulet/coreclr,roncain/coreclr,misterzik/coreclr,jhendrixMSFT/coreclr,jhendrixMSFT/coreclr,pgavlin/coreclr,martinwoodward/coreclr,James-Ko/coreclr,cmckinsey/coreclr,manu-silicon/coreclr,david-mitchell/coreclr,sergey-raevskiy/coreclr,alexperovich/coreclr,Lucrecious/coreclr,Djuffin/coreclr,AlfredoMS/coreclr,alexperovich/coreclr,SpotLabsNET/coreclr,ganeshran/coreclr,richardlford/coreclr,rartemev/coreclr,mokchhya/coreclr,AlexGhiondea/coreclr,mmitche/coreclr,shahid-pk/coreclr,Sridhar-MS/coreclr,wkchoy74/coreclr,AlfredoMS/coreclr,wateret/coreclr,AlexGhiondea/coreclr,geertdoornbos/coreclr,ramarag/coreclr,sagood/coreclr,zmaruo/coreclr,dpodder/coreclr,gitchomik/coreclr,Alcaro/coreclr,GuilhermeSa/coreclr,parjong/coreclr,KrzysztofCwalina/coreclr,grokys/coreclr,ktos/coreclr,mmitche/coreclr,yizhang82/coreclr,sejongoh/coreclr,mskvortsov/coreclr,yeaicc/coreclr,matthubin/coreclr,ganeshran/coreclr,qiudesong/coreclr,fffej/coreclr,fieryorc/coreclr,Samana/coreclr,jakesays/coreclr,benpye/coreclr,jakesays/coreclr,vinnyrom/coreclr,orthoxerox/coreclr,qiudesong/coreclr,SpotLabsNET/coreclr,roncain/coreclr,krixalis/coreclr,cydhaselton/coreclr,SlavaRa/coreclr,iamjasonp/coreclr,wkchoy74/coreclr,neurospeech/coreclr,James-Ko/coreclr,Lucrecious/coreclr,gitchomik/coreclr,Djuffin/coreclr,xtypebee/coreclr,poizan42/coreclr,manu-silicon/coreclr,Godin/coreclr,bartdesmet/coreclr,fernando-rodriguez/coreclr,pgavlin/coreclr,rartemev/coreclr,cshung/coreclr,naamunds/coreclr,ragmani/coreclr,andschwa/coreclr,mmitche/coreclr,Godin/coreclr,neurospeech/coreclr,shahid-pk/coreclr,AlexGhiondea/coreclr,wtgodbe/coreclr,AlfredoMS/coreclr,chaos7theory/coreclr,bartdesmet/coreclr,qiudesong/coreclr,krixalis/coreclr,iamjasonp/coreclr,qiudesong/coreclr,fffej/coreclr,GuilhermeSa/coreclr,zmaruo/coreclr,xoofx/coreclr,Samana/coreclr,ktos/coreclr,sergey-raevskiy/coreclr,wateret/coreclr,jamesqo/coreclr,cydhaselton/coreclr,Dmitry-Me/coreclr,cmckinsey/coreclr,ktos/coreclr,mskvortsov/coreclr,mocsy/coreclr,lzcj4/coreclr,chenxizhang/coreclr,sjsinju/coreclr,russellhadley/coreclr,misterzik/coreclr,Lucrecious/coreclr,benpye/coreclr,wateret/coreclr,chaos7theory/coreclr,fffej/coreclr,zmaruo/coreclr,parjong/coreclr,SlavaRa/coreclr,spoiledsport/coreclr,hanu412/coreclr,wkchoy74/coreclr,cmckinsey/coreclr,hanu412/coreclr,swgillespie/coreclr,chenxizhang/coreclr,josteink/coreclr,blackdwarf/coreclr,LLITCHEV/coreclr,stormleoxia/coreclr,cydhaselton/coreclr,stormleoxia/coreclr,wtgodbe/coreclr,kyulee1/coreclr,pgavlin/coreclr,parjong/coreclr,geertdoornbos/coreclr,shahid-pk/coreclr,ramarag/coreclr,schellap/coreclr,pgavlin/coreclr,ramarag/coreclr,russellhadley/coreclr,hseok-oh/coreclr,xoofx/coreclr,mokchhya/coreclr,chuck-mitchell/coreclr,krk/coreclr,OryJuVog/coreclr,bitcrazed/coreclr,hanu412/coreclr,ytechie/coreclr,naamunds/coreclr,hseok-oh/coreclr,josteink/coreclr,perfectphase/coreclr,blackdwarf/coreclr,ruben-ayrapetyan/coreclr,Godin/coreclr,chenxizhang/coreclr,Godin/coreclr,swgillespie/coreclr,YongseopKim/coreclr,lzcj4/coreclr,neurospeech/coreclr,OryJuVog/coreclr,richardlford/coreclr,swgillespie/coreclr,DasAllFolks/coreclr,jhendrixMSFT/coreclr,krk/coreclr,andschwa/coreclr,mocsy/coreclr,poizan42/coreclr,spoiledsport/coreclr,kyulee1/coreclr,hseok-oh/coreclr,josteink/coreclr,alexperovich/coreclr,matthubin/coreclr,James-Ko/coreclr,ramarag/coreclr,orthoxerox/coreclr,orthoxerox/coreclr,chrishaly/coreclr,grokys/coreclr,LLITCHEV/coreclr,AlexGhiondea/coreclr,jakesays/coreclr,gkhanna79/coreclr,jhendrixMSFT/coreclr,geertdoornbos/coreclr,chaos7theory/coreclr,fieryorc/coreclr,naamunds/coreclr,ramarag/coreclr,bjjones/coreclr,hseok-oh/coreclr,ganeshran/coreclr,schellap/coreclr,ramarag/coreclr,James-Ko/coreclr,russellhadley/coreclr,MCGPPeters/coreclr,tijoytom/coreclr,Lucrecious/coreclr,spoiledsport/coreclr,ericeil/coreclr,ramarag/coreclr,ZhichengZhu/coreclr,serenabenny/coreclr,martinwoodward/coreclr,botaberg/coreclr,cshung/coreclr,Godin/coreclr,libengu/coreclr,sperling/coreclr,alexperovich/coreclr,sagood/coreclr,OryJuVog/coreclr,jakesays/coreclr,JosephTremoulet/coreclr,Sridhar-MS/coreclr,SpotLabsNET/coreclr,ZhichengZhu/coreclr,iamjasonp/coreclr,JonHanna/coreclr,SlavaRa/coreclr,krixalis/coreclr,Sridhar-MS/coreclr,dasMulli/coreclr,dpodder/coreclr,chuck-mitchell/coreclr,JonHanna/coreclr,OryJuVog/coreclr,LLITCHEV/coreclr,ragmani/coreclr,KrzysztofCwalina/coreclr,KrzysztofCwalina/coreclr,shahid-pk/coreclr,JosephTremoulet/coreclr,cydhaselton/coreclr,ericeil/coreclr,mokchhya/coreclr,SpotLabsNET/coreclr,blackdwarf/coreclr,GuilhermeSa/coreclr,qiudesong/coreclr,DasAllFolks/coreclr,DickvdBrink/coreclr,neurospeech/coreclr,naamunds/coreclr,KrzysztofCwalina/coreclr,gkhanna79/coreclr,ruben-ayrapetyan/coreclr,fernando-rodriguez/coreclr,taylorjonl/coreclr,vinnyrom/coreclr,shana/coreclr