Visual Studio Visualizers for ActionResult, LocInfoType, and and TypeSourceInfo

Created a visualizer for ActionResult that displayed the validity and the pointer,
but many of them initially displayed poorly. It turns out that the primary culprit
is that LocInfoType is often passed in an action result, but it is not the same 
as other types. For example, LocInfoType is not in TypeNodes.def and clang::Type::TypeClass
does not have a LocInfoType enum. After adding a special visualizer for LocInfoType,
the display was more useful

llvm-svn: 272487