[clang] [flang] [llvm] [clang][flang][OpenMP] Fix context selector matching and scoring (PR #224431)

[via cfe-commits]

MattPD wrote:

Thanks, both points look addressed. Since the description becomes the commit message, I'd suggest two edits:

- "Correct ... specification-expression contexts" reads as if call sites are covered too. A callee's specification expression lowered at a call site still uses the caller's context, as [the open thread](https://github.com/llvm/llvm-project/pull/224431#discussion_r4096553598) shows. If that stays, could this say "a procedure's own specification expressions"?
- "Diagnose invalid literals without crashing" describes behavior already present on main. The crash existed only between commits of this PR, so could that line go?

https://github.com/llvm/llvm-project/pull/224431