Merge llvm-project main llvmorg-15-init-16436-g18a6ab5b8d1f
This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-15-init-16436-g18a6ab5b8d1f.
PR: 265425
MFC after: 2 weeks
(cherry picked from commit 753f127f3ace09432b2baeffd71a308760641a62)