[HLSL][SPIRV] ByteAddressBuffer InterlockedXYZ methods hit unreachable: Unsupported ptrcast user. Please fix.

Using most ByteAddressBuffer Interlocked methods hits an unreachable in SPIRVLegalizePointerCast ([godbolt](https://hlsl.godbolt.org/z/P89vx3dYY)):
```hlsl
RWByteAddressBuffer Buf : register(u0);

[numthreads(1, 1, 1)]
void main(uint3 GTID : SV_GroupThreadID) {
Buf.InterlockedAnd(0, 1);
}
```

This errors:
```
Unsupported ptrcast user. Please fix.
UNREACHABLE executed at /root/llvm-project/llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp:818!
```

Backtrace:
```
frame #3: 0x00000001035d898c clang-dxc`llvm::llvm_unreachable_internal(char const*, char const*, unsigned int) + 552
frame #4: 0x00000001018e3c40 clang-dxc`(anonymous namespace)::SPIRVLegalizePointerCastImpl::legalizePointerCast(this=0x000000016fdf2e58, II=0x00000008cf128160) at SPIRVLegalizePointerCast.cpp:818:7
frame #5: 0x00000001018e2f4c clang-dxc`(anonymous namespace)::SPIRVLegalizePointerCastImpl::run(this=0x000000016fdf2e58, F=0x00000008ced7c468) at SPIRVLegalizePointerCast.cpp:842:7
frame #6: 0x00000001018f3bd8 clang-dxc`(anonymous namespace)::SPIRVLegalizePointerCastLegacy::runOnFunction(this=0x00000008cf804930, F=0x00000008ced7c468) at SPIRVLegalizePointerCast.cpp:863:45
```