Reland r219810 "Fix late template parsing leak with incremental processing"
Original message:
Add a second late template parser callback meant to cleanup any
resources allocated by late template parsing. Call it from the
Sema::ActOnEndOfTranslationUnit method after all pending template
instantiations have been completed. Teach Parser::ParseTopLevelDecl to
install the cleanup callback when incremental processing is enabled so
that Parser::TemplateIds can be freed.
Patch by Brad King!
llvm-svn: 220400