Revert "DebugInfo: Omit debug info for dynamic classes in TUs that do not have the vtable for that class"

This reverts commit r188576.

Reverting while I investigate a selfhosting buildbot failure on Darwin.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188600 91177308-0d34-0410-b5e6-96231b3b80d8