[clang] [OpenACC][CIR] Implement beginning of 'copy' lowering for compute con… (PR #140304)

[Bruno Cardoso Lopes via cfe-commits]

https://github.com/bcardosolopes commented:

A question in the comments but otherwise PR looks good: adds boilerplate and initial cases, deferring more work for incremental PRs, way to go.

https://github.com/llvm/llvm-project/pull/140304