[clang] [llvm] [NVPTX] Support i256 load/store with 256-bit vector load (PR #155198)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

@AlexMaclean This broke a lot of buildbots (including premerge), most likely due to a midair collision. Can you update the test or revert?

https://github.com/llvm/llvm-project/pull/155198