[HLSL] Root Signature semantic analysis - Register Validations

[inbelic]

This issue handles the additional semantic analysis of the parsed HLSLRootSignature attribute. This includes generating applicable diagnostics.

The relevant validations that this issue must implement are:

• Validate that resource ranges don't overlap
• Ensure that registers are only bound once

See previous validation implementation for reference on range analysis.

Dependent on: #126577 and #126569

AC:

• Update ParseHLSLRootSignature defined in [HLSL] Generate AST for Root Signatures #119011 to implement semantic validation of HLSLRootSignature
• Update handleHLSLRootSignature to implement semantic validation of HLSLRootSignature in SemaHLSL.cpp
• Add thorough testing of correct diagnostics into clang/unittests/Sema/ParseHLSLRootSignatureTest.cpp
• Add tests for some samples to ensure diagnostics are displayed correctly from HLSL input in AST/HLSL/RootSignatures-AST.hlsl

[inbelic]

I have a local patch ready to go but it is blocked for review based on the resolution of: #119011