Revert "cpp11-migrate: Add a class to support include directives modifications"

This reverts commit r188610.

Issue with the absolute include paths not found in the unit tests on the Windows
bots. Needs investigation.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@188611 91177308-0d34-0410-b5e6-96231b3b80d8