[clang] [OpenMP] Add runtime selection for metadirective with non-constant conditions. (PR #192455)

[Zahira Ammarguellat via cfe-commits]

zahiraam wrote:

Thinking about it a little more, I think for the compile-time resolvable conditions, the resulting AST should discard the `metadirective`, right? It's kept only for **non**-compile-time resolvable conditions. In which case my code is wrong. Can you please confirm?

https://github.com/llvm/llvm-project/pull/192455