Summary:
* Support rename alias.
* Add unittests for renaming alias.
* Don't generate fixes for the SourceLocations that are invalid or in temporary
buffer, otherwise crash would be happened when generating AtomicChanges.
Reviewers: ioeric
Reviewed By: ioeric
Subscribers: klimek, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D39043
llvm-svn: 316074
Haojian Wu