Tests can not be adopted 1:1 (e.g. Clang-Rename modifies namespace for some
symbols) and some tests appear to not be working due to our selection/other
factors. However, this helps us expose some unexpected bugs and prepares for
the decl canonicalization fix (D71880).
The adopted cases are from Clang-Rename's RenameAliasTest.cpp unittest.
Previous patch in the chain: D91102.