Push nested-name-specifier source location information into elaborated

Push nested-name-specifier source location information into elaborated
name types, e.g., "enum clang::NestedNameSpecifier::SpecifierKind".

Aside from the normal changes, this also required some tweaks to the
parser. Essentially, when we're looking at a type name (via
getTypeName()) specifically for the purpose of creating an annotation
token, we pass down the flag that asks for full type-source location
information to be stored within the returned type. That way, we retain
source-location information involving nested-name-specifiers rather
than trying to reconstruct that information later, long after it's
been lost in the parser.

With this change, test/Index/recursive-cxx-member-calls.cpp is showing
much improved results again, since that code has lots of
nested-name-specifiers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126737 91177308-0d34-0410-b5e6-96231b3b80d8