[llvm] [SPIRV] Expand RWBuffer load and store from HLSL (PR #122355)

[Nathan Gauër via llvm-commits]

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Keenuts wrote:

If the goal is to restore this test once the implementation is stable, I'd say `XFAIL` with a context issue/pr so we know why?

https://github.com/llvm/llvm-project/pull/122355