[clang-tidy] Treat references to smart pointers correctly in use-after-move.

Summary:
Previously, we weren't recognizing these as smart pointers and thus
weren't allowing non-dereference accesses as we should -- see new test
cases which fail without the fix.

Reviewers: alexfh, hokein, aaron.ballman, JonasToth

Reviewed By: JonasToth

Subscribers: xazax.hun, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D56585

llvm-svn: 351303