Use unique_ptr to remove some explicit deletes on some error case returns. At least one spot of weird ownership passing that needs some future cleanup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222947 91177308-0d34-0410-b5e6-96231b3b80d8
Make RecordKeeper::addClass/addDef take unique_ptrs instead of creating one internally.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222948 91177308-0d34-0410-b5e6-96231b3b80d8