This is in preparation for adding other overloaded matchers. This change
alone is a net win in LOC.
I went through all matchers and looked whether we could now encode them
as macro, or simplify them with the matcher atoms that were not
available before.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174540 91177308-0d34-0410-b5e6-96231b3b80d8