[clang] [HLSL] Adjust resource binding diagnostic flags code (PR #106657)

[Kazu Hirata via cfe-commits]

kazutakahirata wrote:

I've fixed the warnings from this PR with b2dabd2b06cb0ca5ea534bafe33c5cff5521be18.

Now, I'm not familiar with the code here, but is it still important to do the consistency check on these two variables if you don't use them in `DiagnoseHLSLRegisterAttribute` at all other than in the `assert`?  If not, you might want to just remove the block of code.  Thanks!

```
  // Samplers, UAVs, and SRVs are VarDecl types
  VarDecl *TheVarDecl = dyn_cast<VarDecl>(TheDecl);
  // Cbuffers and Tbuffers are HLSLBufferDecl types
  HLSLBufferDecl *CBufferOrTBuffer = dyn_cast<HLSLBufferDecl>(TheDecl);
  // exactly one of these two types should be set
  assert(((TheVarDecl && !CBufferOrTBuffer) ||
          (!TheVarDecl && CBufferOrTBuffer)) &&
         "either TheVarDecl or CBufferOrTBuffer should be set");
  (void)TheVarDecl;
  (void)CBufferOrTBuffer;```


https://github.com/llvm/llvm-project/pull/106657