This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp to llvm-project release/18.x llvmorg-18.1.0-rc2-0-gc6c86965d967. PR: 276104 MFC after: 1 month
This updates llvm, clang, compiler-rt, libc++, libunwind, lld, lldb and openmp to llvm-project main llvmorg-17-init-19304-gd0b54bb50e51, the last commit before the upstream release/17.x branch was created. PR: 273753 MFC after: 1 month
