[clang] [CIR][OpenMP] Implement lowering for the 'num_threads' clause for 'parallel' directive (PR #202466)

[Pedro da Rosa Pinheiro via cfe-commits]

pedropiin wrote:

Hi @skatrak @bcardosolopes @xlauko could you please take a look and help me merge this? The only failed CI is the Linux build, with timeout issues in unrelated tests.

https://github.com/llvm/llvm-project/pull/202466