Better implementation of JavaScript === and !== operators.

Summary:
Now based on token merging. Now they are not only prevented from being
split, but are actually formatted as comparison operators.

Reviewers: djasper, klimek

Reviewed By: klimek

CC: cfe-commits, klimek

Differential Revision: http://llvm-reviews.chandlerc.com/D2240

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195354 91177308-0d34-0410-b5e6-96231b3b80d8