[DirectX] DXContainer PSV0 part Object support

[llvm-beanz]

Summary

Add support for parsing and generating pipeline state validation data structures encoded in the PSV0 part. Parsing code should be added to libLLVMObject, with support in libLLVMObjectYAML for textual representation of the binary data. Support for emitting binary encoded PSV data should be split between the ObjectYAML emitter used for testing and the MC layer for generation of data structures from the compiler.

References

A description of the current object encoding is in the DXC code here:
https://github.com/microsoft/DirectXShaderCompiler/blob/main/include/dxc/DxilContainer/DxilPipelineStateValidation.h#L731

Deliverables

Updated obj2yaml and yaml2obj tools to which support extracting and encoding PSV0 data, and associated tests. Tests should verify correct round-trip parse->generate->parse for common variations and versioning of the data structures.

[llvm-beanz]

Posted another part of this for review as D155143.