[llvm] [AMDGPU][NewPM] Port AMDGPUOpenCLEnqueuedBlockLowering to NPM (PR #122434)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Since this is an IR pass, it could be tested as a standalone pass with opt - but it cannot be since the generic PassBuilder does not know about it in opt.

It can be tested, we already test many backend IR passes this way 

https://github.com/llvm/llvm-project/pull/122434