[clang] [llvm] [NFC][HLSL][DXIL] Move D3D12.h enums and flags to DXILABI (PR #143041)

[Finn Plummer via llvm-commits]

inbelic wrote:

I will mark this as draft until I re-update it to use the values from DXContainer.h. Some of the enums are not yet defined, so either we will wait until they are defined to refactor, or, we can define them here.

https://github.com/llvm/llvm-project/pull/143041