Revert "Revert "[NFC] Refactor DiagnosticRenderer to use FullSourceLoc""

This reverts commit r305688 meaning it reintroduces r305684. To repeat:

[NFC] Refactor DiagnosticRenderer to use FullSourceLoc

Move the DiagnosticRenderer and its dependents to using FullSourceLocs
instead of a SourceLocation and SourceManager pointer. The changeset is
rather large but entirely mechanical.

This is step one to allow DiagnosticRenderer to take either
llvm::SMLocs or clang::SourceLocations.

This breaks clang-tidy and clng-query which will be fixed in a commit
soon after.

Patch by Sanne Wouda

Differential Revision: https://reviews.llvm.org/D31709

llvm-svn: 306384