[llvm-objdump] - An attempt to fix BB after r337361.

Seems r337361 is the reason of the following ARM BB failures:
http://lab.llvm.org:8011/builders/clang-cmake-armv8-quick
http://lab.llvm.org:8011/builders/clang-cmake-armv8-full/builds/4633

Reason is unclear to me, other bots are OK.
If this will not help, I'll revert r337361.

llvm-svn: 337371