Update StringObject comment in object.h (#5011)
Update StringObject comment in object.h (#5011)

* m_ArrayLength is no longer present (I did a search of the source and couldn't find it), so this comment is misleading.
* Also removing mis-leading comment about high two bits of field
JosephTremoulet/coreclr,rartemev/coreclr,poizan42/coreclr,cshung/coreclr,jamesqo/coreclr,LLITCHEV/coreclr,neurospeech/coreclr,neurospeech/coreclr,qiudesong/coreclr,mmitche/coreclr,naamunds/coreclr,jhendrixMSFT/coreclr,hseok-oh/coreclr,ruben-ayrapetyan/coreclr,neurospeech/coreclr,ZhichengZhu/coreclr,schellap/coreclr,josteink/coreclr,qiudesong/coreclr,ZhichengZhu/coreclr,roncain/coreclr,YongseopKim/coreclr,russellhadley/coreclr,schellap/coreclr,russellhadley/coreclr,KrzysztofCwalina/coreclr,wtgodbe/coreclr,ZhichengZhu/coreclr,shahid-pk/coreclr,dpodder/coreclr,bartdesmet/coreclr,JonHanna/coreclr,ramarag/coreclr,cydhaselton/coreclr,krk/coreclr,mskvortsov/coreclr,alexperovich/coreclr,yeaicc/coreclr,naamunds/coreclr,gkhanna79/coreclr,alexperovich/coreclr,wtgodbe/coreclr,josteink/coreclr,dpodder/coreclr,yeaicc/coreclr,bartdesmet/coreclr,roncain/coreclr,wtgodbe/coreclr,cydhaselton/coreclr,krytarowski/coreclr,rartemev/coreclr,neurospeech/coreclr,bartdesmet/coreclr,sjsinju/coreclr,yeaicc/coreclr,schellap/coreclr,ramarag/coreclr,josteink/coreclr,Dmitry-Me/coreclr,shahid-pk/coreclr,bartdesmet/coreclr,jamesqo/coreclr,Dmitry-Me/coreclr,mmitche/coreclr,JosephTremoulet/coreclr,cshung/coreclr,jhendrixMSFT/coreclr,krytarowski/coreclr,qiudesong/coreclr,pgavlin/coreclr,yeaicc/coreclr,ragmani/coreclr,JosephTremoulet/coreclr,cydhaselton/coreclr,manu-silicon/coreclr,parjong/coreclr,schellap/coreclr,AlexGhiondea/coreclr,poizan42/coreclr,krk/coreclr,Dmitry-Me/coreclr,kyulee1/coreclr,vinnyrom/coreclr,shahid-pk/coreclr,ragmani/coreclr,sagood/coreclr,manu-silicon/coreclr,tijoytom/coreclr,Dmitry-Me/coreclr,vinnyrom/coreclr,JonHanna/coreclr,ramarag/coreclr,bartdesmet/coreclr,pgavlin/coreclr,kyulee1/coreclr,hseok-oh/coreclr,James-Ko/coreclr,mskvortsov/coreclr,jhendrixMSFT/coreclr,JosephTremoulet/coreclr,bartdesmet/coreclr,krytarowski/coreclr,KrzysztofCwalina/coreclr,tijoytom/coreclr,JonHanna/coreclr,LLITCHEV/coreclr,pgavlin/coreclr,vinnyrom/coreclr,roncain/coreclr,rartemev/coreclr,manu-silicon/coreclr,shahid-pk/coreclr,alexperovich/coreclr,jamesqo/coreclr,hseok-oh/coreclr,ZhichengZhu/coreclr,botaberg/coreclr,krytarowski/coreclr,roncain/coreclr,ruben-ayrapetyan/coreclr,cmckinsey/coreclr,botaberg/coreclr,qiudesong/coreclr,cshung/coreclr,AlexGhiondea/coreclr,Dmitry-Me/coreclr,schellap/coreclr,wateret/coreclr,JonHanna/coreclr,James-Ko/coreclr,jhendrixMSFT/coreclr,wateret/coreclr,vinnyrom/coreclr,naamunds/coreclr,AlexGhiondea/coreclr,schellap/coreclr,tijoytom/coreclr,pgavlin/coreclr,sjsinju/coreclr,yeaicc/coreclr,LLITCHEV/coreclr,KrzysztofCwalina/coreclr,Dmitry-Me/coreclr,wtgodbe/coreclr,yeaicc/coreclr,josteink/coreclr,yeaicc/coreclr,dpodder/coreclr,AlexGhiondea/coreclr,manu-silicon/coreclr,martinwoodward/coreclr,parjong/coreclr,cydhaselton/coreclr,hseok-oh/coreclr,tijoytom/coreclr,josteink/coreclr,schellap/coreclr,yizhang82/coreclr,mmitche/coreclr,parjong/coreclr,poizan42/coreclr,gkhanna79/coreclr,jamesqo/coreclr,alexperovich/coreclr,naamunds/coreclr,jhendrixMSFT/coreclr,sagood/coreclr,dpodder/coreclr,russellhadley/coreclr,tijoytom/coreclr,martinwoodward/coreclr,mskvortsov/coreclr,mskvortsov/coreclr,gkhanna79/coreclr,sjsinju/coreclr,dpodder/coreclr,cshung/coreclr,botaberg/coreclr,krk/coreclr,mmitche/coreclr,hseok-oh/coreclr,YongseopKim/coreclr,manu-silicon/coreclr,Dmitry-Me/coreclr,mmitche/coreclr,sjsinju/coreclr,dasMulli/coreclr,vinnyrom/coreclr,roncain/coreclr,russellhadley/coreclr,LLITCHEV/coreclr,ramarag/coreclr,sagood/coreclr,russellhadley/coreclr,ragmani/coreclr,ruben-ayrapetyan/coreclr,LLITCHEV/coreclr,kyulee1/coreclr,dpodder/coreclr,yizhang82/coreclr,pgavlin/coreclr,JosephTremoulet/coreclr,cmckinsey/coreclr,ZhichengZhu/coreclr,poizan42/coreclr,gkhanna79/coreclr,ragmani/coreclr,martinwoodward/coreclr,wtgodbe/coreclr,alexperovich/coreclr,yizhang82/coreclr,mskvortsov/coreclr,dasMulli/coreclr,vinnyrom/coreclr,botaberg/coreclr,rartemev/coreclr,shahid-pk/coreclr,ruben-ayrapetyan/coreclr,pgavlin/coreclr,AlexGhiondea/coreclr,cshung/coreclr,wateret/coreclr,tijoytom/coreclr,krytarowski/coreclr,ZhichengZhu/coreclr,naamunds/coreclr,josteink/coreclr,KrzysztofCwalina/coreclr,AlexGhiondea/coreclr,JosephTremoulet/coreclr,josteink/coreclr,neurospeech/coreclr,shahid-pk/coreclr,botaberg/coreclr,jamesqo/coreclr,yizhang82/coreclr,rartemev/coreclr,yizhang82/coreclr,ruben-ayrapetyan/coreclr,ramarag/coreclr,cshung/coreclr,sjsinju/coreclr,cmckinsey/coreclr,ragmani/coreclr,wtgodbe/coreclr,martinwoodward/coreclr,hseok-oh/coreclr,YongseopKim/coreclr,JonHanna/coreclr,mmitche/coreclr,dasMulli/coreclr,LLITCHEV/coreclr,krk/coreclr,KrzysztofCwalina/coreclr,mskvortsov/coreclr,botaberg/coreclr,James-Ko/coreclr,krytarowski/coreclr,gkhanna79/coreclr,dasMulli/coreclr,manu-silicon/coreclr,cydhaselton/coreclr,martinwoodward/coreclr,shahid-pk/coreclr,poizan42/coreclr,James-Ko/coreclr,krk/coreclr,sagood/coreclr,russellhadley/coreclr,YongseopKim/coreclr,poizan42/coreclr,KrzysztofCwalina/coreclr,ragmani/coreclr,YongseopKim/coreclr,gkhanna79/coreclr,roncain/coreclr,wateret/core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