Remove DIBuilder cache of variable TheCU and change the few
uses that wanted it. Also change the interface for createCompileUnit
to compensate. Fix comments that refer to TheCU as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186599 91177308-0d34-0410-b5e6-96231b3b80d8
Equal means ==, not !=. Thanks to Benjamin for catching.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186600 91177308-0d34-0410-b5e6-96231b3b80d8