Use CharInfo.h routines in TextComment::isWhitespaceNoCache


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189115 91177308-0d34-0410-b5e6-96231b3b80d8
Fix indentation


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189119 91177308-0d34-0410-b5e6-96231b3b80d8