[NVPTX] Don't use stack memory when bitcasting to/from v2i8#113928

ThomasRaoux merged 6 commits intollvm:mainllvm/llvm-project:mainfrom

peterbell10:nvptx-v2i8-no-stackpeterbell10/llvm-project:nvptx-v2i8-no-stackCopy head branch name to clipboard