[OpenMP][clang] 6.0: parsing/sema for num_threads 'strict' modifier (#145490)

Implement parsing and semantic analysis support for the optional
'strict' modifier of the num_threads clause. This modifier has been
introduced in OpenMP 6.0, section 12.1.2.

Note: this is basically 1:1 https://reviews.llvm.org/D138328.
GitOrigin-RevId: f624ba2d9d2143a0c2679ee9792cf455f965adec
1 file changed