Fix crash-on-invalid with inheriting constructor.

Fixes PR16656.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186631 91177308-0d34-0410-b5e6-96231b3b80d8
Update createCompileUnit call for llvm changes.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186638 91177308-0d34-0410-b5e6-96231b3b80d8