Workaround ASTMatcher crashes. Added some more test cases.
Summary:
- UsingDecl matcher crashed when `UsingShadowDecl` has no parent map. Workaround by moving parent check into `UsingDecl`.
- FunctionDecl matcher crashed when there is a lambda defined in parameter list (also due to no parent map).
Workaround by putting `unless(cxxMethodDecl())` before parent check.
Reviewers: klimek, sbenza, aaron.ballman, hokein
Subscribers: aaron.ballman, cfe-commits
Differential Revision: https://reviews.llvm.org/D24862
llvm-svn: 282486