Merge llvm-project release/15.x llvmorg-15.0.0-9-g1c73596d3454
This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-15.0.0-9-g1c73596d3454.
PR: 265425
MFC after: 2 weeks
(cherry picked from commit a4a491e2238b12ccd64d3faf9e6401487f6f1f1b)