[Sema/Attribute] Make types declared with address_space an AttributedType

Currently an address_space is stored in a qualifier. This makes any type
declared with an address_space attribute in the form
`__attribute__((address_space(1))) int 1;` be wrapped in an AttributedType.

This is for a later patch where if `address_space` is declared in a macro,
any diagnostics that would normally print the address space will instead dump
the macro name. This will require saving any macro information in the
AttributedType.

Differential Revision: https://reviews.llvm.org/D51229

llvm-svn: 340765