Change public functions of LTOCodeGenerator from ret-false-on-succ to ret-true-on-succ.

As of this revision, all functions of LTOCodeGenerator are consistent in
ret-true-on-succ.

Tested on multiple OSes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187864 91177308-0d34-0410-b5e6-96231b3b80d8