[SPIR-V] Use `OpImageFetch` instead of `OpImageRead` when loading from read-only `Buffer` resource. (#163626)

Currently, the spir-v validator fails if `OpImageRead` instruction is
used when loading from read-only `Buffer`.
### Unit Test
```hlsl
RWBuffer<uint> rwbuff;
Buffer<uint>  buff;

[numthreads(1,1,1)]
void main() {
    rwbuff[99] = buff[98];
    rwbuff[97] = rwbuff[96];
}
```
This also unblocks adding a test case that adds a special capability
when using a non-uniform index on `Buffer` arrays.
(https://github.com/llvm/llvm-project/pull/162540).

Resolves https://github.com/llvm/llvm-project/issues/162891

0 files changed, 0 insertions, 0 deletions