cpp11-migrate: Tidying up

* Some file headers were missing for files in Core/
* Some headers were included but not necessary
* CMakeLists.txt was linking in LLVMSupport even though CMakeLists in subdirs
  were linking it in too.
* StringRefisation of constructors of types in FileOverrides.h
* Other misc cleanups

Author: Guillaume Papin <guillaume.papin@epitech.eu>



git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@185811 91177308-0d34-0410-b5e6-96231b3b80d8
cpp11-migrate: Fixes for r185811

Some changes to r185811 broke certain build configurations. These changes should
fix them.

Author: Guillaume Papin <guillaume.papin@epitech.eu>



git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@185814 91177308-0d34-0410-b5e6-96231b3b80d8