Revert [Bugpoint redesign] Added Pass to Remove Global Variables

This reverts r368918 because it was unstable!

It broke these builds:
 * http://lab.llvm.org:8011/builders/lld-x86_64-ubuntu-fast/builds/4649
 * http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29966
 * http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29964

But surprisingly this passed:
 * http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29965

llvm-svn: 369039