[clang] [OpenACC][CIR] 'cache' construct lowering (PR #146915)

[Bruno Cardoso Lopes via cfe-commits]

bcardosolopes wrote:

> This did require some work to ensure that the cache doesn't have 'vars' that aren't inside of the loop, but Sema is taking care of that with a warning

Because it's a warning, is there anything we can add to existing verifiers to sanity check the invariant?

https://github.com/llvm/llvm-project/pull/146915