[OpenMP] Fix issue with directives used in a macro.
If directives are used in a macro, clang complains with:
src/projects/openmp/runtime/src/kmp_runtime.c:7486:2: error: embedding a directive within macro arguments has undefined behavior [-Werror,-Wembedded-directive] #if KMP_USE_MONITOR
This patch fixes two occurrences of the issue in kmp_runtime.cpp.
Reviewers: tlwilmar, jlpeyton, AndreyChurbanov, Hahnfeld
Subscribers: Hahnfeld, openmp-commits
Differential Revision: https://reviews.llvm.org/D25823