Re-sort all the headers. Lots of regressions have crept in here.
Manually fix the order of UnwrappedLineParser.cpp as that one didn't
have its associated header as the first header.

This also uncovered a subtle inclusion order dependency as CLog.h didn't
include LLVM.h to pick up using declarations it relied upon.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172892 91177308-0d34-0410-b5e6-96231b3b80d8