Adding an AST matcher to ignore parenthesis in *types* (rather than...

Adding an AST matcher to ignore parenthesis in *types* (rather than expressions). This is required for traversing certain types (like function pointer types).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@271927 91177308-0d34-0410-b5e6-96231b3b80d8