Implement ClrDataTypeInstance GetName and GetDefinition in cDAC

[Copilot]

Implements cDAC-native ClrDataTypeInstance name and definition resolution without metadata-cache fallback.

Changes

• Format names through the managed type-handle path with HRESULT and debug validation.
• Resolve definitions across arrays, function pointers, parameterized types, and unloaded TypeDefs.
• Add module, token, and nullable type-handle state to ClrDataTypeDefinition without implementing its APIs.
• Add cross-architecture coverage for buffer handling and definition resolution.

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[azure-pipelines]

Azure Pipelines:
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There may be pipelines that require an authorized user to comment /azp run to run.

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