Merge llvm-project release/15.x llvmorg-15.0.0-rc2-40-gfbd2950d8d0d
This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvmorg-15.0.0-rc2-40-gfbd2950d8d0d.
PR: 265425
MFC after: 2 weeks
(cherry picked from commit 61cfbce3347e4372143bcabf7b197577b9f3958a)