Summary:
Rewrite eachOf/allOf/anyOf to use a variadic operator, instead of hand-written calls to Polymorphic matchers.
This simplifies their definition and future changes to add them to the dynamic registry.

Reviewers: klimek

CC: cfe-commits, revane

Differential Revision: http://llvm-reviews.chandlerc.com/D1427

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189357 91177308-0d34-0410-b5e6-96231b3b80d8