Merge llvm-project release/18.x llvmorg-18.1.0-rc2-53-gc7b0a6ecd442
This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and
openmp to llvm-project release/18.x llvmorg-18.1.0-rc2-53-gc7b0a6ecd442.
PR: 276104
MFC after: 1 month
(cherry picked from commit 74626c16ff489c0d64cf2843dfd522e7c544f3ce)