[bugpoint] Fix crash when testing for miscompilation.

Method BugDriver::performFinalCleanups(...) would delete Module object
it worked on, which was also deleted by its caller
(e.g. TestCodeGenerator(...)). Changed the code to avoid double delete
and make Module ownership slightly clearer.

Patch by Andrzej Janik.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330763 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed