Fix the 4203-Buildbot failure in LLVM Buildbot on llvm-clang-win-x-aarch64

    Failure in llvm/test/tools/llvm-objdump/XCOFF/section-headers.test:

    SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes
                 in position 24-25: truncated \xXX escape