More gracefully handle parentheses in templare arguments in template diffing.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213611 91177308-0d34-0410-b5e6-96231b3b80d8
Fix '&' printing for template arguments in parentheses in template diffing.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@213613 91177308-0d34-0410-b5e6-96231b3b80d8