[x86/Linux] Fix UMThunkStub calling convension (#8714)
[x86/Linux] Fix UMThunkStub calling convension (#8714)

This fixes reverse P/Invoke segment faults by handling cdecl from UM to
fastcall for Managed code, which corrects many CoreFX unit test cases including CharMinValue.exe.
First and second parameter(s) are set to ECX, EDX and rest to the stack.
krytarowski/coreclr,krytarowski/coreclr,parjong/coreclr,JonHanna/coreclr,sjsinju/coreclr,ragmani/coreclr,ruben-ayrapetyan/coreclr,sjsinju/coreclr,botaberg/coreclr,botaberg/coreclr,yizhang82/coreclr,gkhanna79/coreclr,James-Ko/coreclr,cmckinsey/coreclr,cydhaselton/coreclr,pgavlin/coreclr,mskvortsov/coreclr,JonHanna/coreclr,parjong/coreclr,kyulee1/coreclr,dpodder/coreclr,poizan42/coreclr,James-Ko/coreclr,yizhang82/coreclr,sagood/coreclr,hseok-oh/coreclr,AlexGhiondea/coreclr,wtgodbe/coreclr,cydhaselton/coreclr,alexperovich/coreclr,YongseopKim/coreclr,pgavlin/coreclr,kyulee1/coreclr,pgavlin/coreclr,hseok-oh/coreclr,poizan42/coreclr,krk/coreclr,cydhaselton/coreclr,botaberg/coreclr,rartemev/coreclr,krytarowski/coreclr,JosephTremoulet/coreclr,yeaicc/coreclr,tijoytom/coreclr,gkhanna79/coreclr,sjsinju/coreclr,yeaicc/coreclr,James-Ko/coreclr,kyulee1/coreclr,mmitche/coreclr,JonHanna/coreclr,krk/coreclr,tijoytom/coreclr,wtgodbe/coreclr,ragmani/coreclr,russellhadley/coreclr,cshung/coreclr,qiudesong/coreclr,qiudesong/coreclr,alexperovich/coreclr,cshung/coreclr,wtgodbe/coreclr,mmitche/coreclr,YongseopKim/coreclr,wtgodbe/coreclr,wtgodbe/coreclr,gkhanna79/coreclr,YongseopKim/coreclr,neurospeech/coreclr,yeaicc/coreclr,James-Ko/coreclr,tijoytom/coreclr,poizan42/coreclr,russellhadley/coreclr,ragmani/coreclr,rartemev/coreclr,sjsinju/coreclr,jamesqo/coreclr,JosephTremoulet/coreclr,yizhang82/coreclr,yeaicc/coreclr,hseok-oh/coreclr,jamesqo/coreclr,krk/coreclr,botaberg/coreclr,qiudesong/coreclr,wateret/coreclr,cydhaselton/coreclr,ragmani/coreclr,jamesqo/coreclr,tijoytom/coreclr,pgavlin/coreclr,krk/coreclr,cmckinsey/coreclr,rartemev/coreclr,krk/coreclr,russellhadley/coreclr,parjong/coreclr,krk/coreclr,mmitche/coreclr,rartemev/coreclr,dpodder/coreclr,mskvortsov/coreclr,botaberg/coreclr,mskvortsov/coreclr,wtgodbe/coreclr,qiudesong/coreclr,AlexGhiondea/coreclr,poizan42/coreclr,AlexGhiondea/coreclr,JosephTremoulet/coreclr,sagood/coreclr,pgavlin/coreclr,qiudesong/coreclr,alexperovich/coreclr,neurospeech/coreclr,russellhadley/coreclr,dpodder/coreclr,yizhang82/coreclr,jamesqo/coreclr,parjong/coreclr,cshung/coreclr,YongseopKim/coreclr,mmitche/coreclr,mskvortsov/coreclr,krytarowski/coreclr,alexperovich/coreclr,kyulee1/coreclr,mmitche/coreclr,JosephTremoulet/coreclr,mmitche/coreclr,rartemev/coreclr,JosephTremoulet/coreclr,parjong/coreclr,JonHanna/coreclr,wateret/coreclr,russellhadley/coreclr,botaberg/coreclr,AlexGhiondea/coreclr,dpodder/coreclr,cmckinsey/coreclr,qiudesong/coreclr,gkhanna79/coreclr,yeaicc/coreclr,cmckinsey/coreclr,cydhaselton/coreclr,sagood/coreclr,cydhaselton/coreclr,parjong/coreclr,neurospeech/coreclr,poizan42/coreclr,sjsinju/coreclr,neurospeech/coreclr,yeaicc/coreclr,neurospeech/coreclr,ragmani/coreclr,cshung/coreclr,alexperovich/coreclr,hseok-oh/coreclr,russellhadley/coreclr,sjsinju/coreclr,yizhang82/coreclr,kyulee1/coreclr,neurospeech/coreclr,cmckinsey/coreclr,kyulee1/coreclr,gkhanna79/coreclr,wateret/coreclr,ruben-ayrapetyan/coreclr,JonHanna/coreclr,cshung/coreclr,cmckinsey/coreclr,wateret/coreclr,sagood/coreclr,krytarowski/coreclr,yeaicc/coreclr,YongseopKim/coreclr,dpodder/coreclr,jamesqo/coreclr,cshung/coreclr,James-Ko/coreclr,ruben-ayrapetyan/coreclr,tijoytom/coreclr,wateret/coreclr,James-Ko/coreclr,mskvortsov/coreclr,krytarowski/coreclr,AlexGhiondea/coreclr,wateret/coreclr,gkhanna79/coreclr,ragmani/coreclr,cmckinsey/coreclr,JosephTremoulet/coreclr,ruben-ayrapetyan/coreclr,pgavlin/coreclr,rartemev/coreclr,ruben-ayrapetyan/coreclr,hseok-oh/coreclr,alexperovich/coreclr,tijoytom/coreclr,JonHanna/coreclr,jamesqo/coreclr,sagood/coreclr,hseok-oh/coreclr,AlexGhiondea/coreclr,sagood/coreclr,YongseopKim/coreclr,ruben-ayrapetyan/coreclr,poizan42/coreclr,yizhang82/coreclr,dpodder/coreclr,mskvortsov/coreclr