Update resource metadata tests to generate metadata based on
`llvm.dx.resource.handlefrombinding` data collected in
`DXILResourceBindingAnalysis`.
- `UAVMetadata.ll` is updated, renamed to `uav_metadata.ll`, and placed
under `Metadata` directory in `llvm/test/CodeGen/DirectX`
- `srv_metadata.ll` is a new test for SRV resource metadata
- `cbuf.ll` and `legacy_cb_layout_{0|1}.ll` tests were merged into
`cbuffer_metadata.ll`
- `legacy_cb_layout_{2|3}.ll` tests we moved to `cbuffer.hlsl` in Clang
CodeGen because there were more of a layout than metadata tests
Related to [#114126](https://github.com/llvm/llvm-project/issues/114126)
8d7cb5d05b