[OpenMP] Add strict mode in num_tasks and grainsize

This patch adds new API __kmpc_taskloop_5 to accomadate strict
modifier (introduced in OpenMP 5.1) in num_tasks and grainsize
clause.

Differential Revision: https://reviews.llvm.org/D92352

GitOrigin-RevId: 540007b42701b5ac9adba076824bfd648a265413
4 files changed