Revert my patches which removed Diagnostic.h includes by moving some operator...

Revert my patches which removed Diagnostic.h includes by moving some operator overloads out of line.

This seems to negatively affect compile time onsome ObjC tests
(which use a lot of partial diagnostics I assume). I have to come
up with a way to keep them inline without including Diagnostic.h
everywhere. Now adding a new diagnostic requires a full rebuild
of e.g. the static analyzer which doesn't even use those diagnostics.

This reverts commit 6496bd10.
This reverts commit 7af19b81.
This reverts commit fdd15602.
This reverts commit 00bd44d5.
This reverts commit ef9b60ff.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150006 91177308-0d34-0410-b5e6-96231b3b80d8