Add support for a verifier to the driver. Currently only verifies debug
output on darwin so is hard coded there.

As a note this will need a little bit of refactoring in the class
hierarchy to separate it out for different verifiers based on input type.

Fixes rdar://8256258.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138343 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed