[llvm] [SPIRV] Return success when selecting reads and writes. (PR #122162)

[Steven Perron via llvm-commits]

s-perron wrote:

The SPIR-V test failures were caused by an update in spirv-val (https://github.com/KhronosGroup/SPIRV-Tools/pull/5407). Unrelated to this change.

@VyacheslavLevytskyy who would be responsible for fixing the failing tests:

```
Failed Tests (4):
  LLVM :: CodeGen/SPIRV/pointers/type-deduce-sycl-stub.ll
  LLVM :: CodeGen/SPIRV/transcoding/OpGroupBroadcast.ll
  LLVM :: CodeGen/SPIRV/validate/sycl-hier-par-basic.ll
  LLVM :: CodeGen/SPIRV/validate/sycl-tangle-group-algorithms.ll
```

https://github.com/llvm/llvm-project/pull/122162