Add Visual Studio native visualizers for several Clang types

This is one of a series of changes to improve the MSVC visualization of Clang types.
This one focuses on Record and SubstTemplateTypeParmType meaning that, for example,
a TemplateArgumentLoc no longer displays incomprehensibly in the locals window as

  {Argument={DeclArg={Kind=1 QT=0x033acb00 D=0xcccccccc {DeclType=???}}...

but instead much more usefully as

  Type template parameter: SubstTemplateTypeParm: {Identifier (("T"))} => Record, {Identifier (("A"))}

Additional types and improvements will be made in subsequent commits

llvm-svn: 262933