swift234

[Clang importer] Mark redundant "Ref" aliases of CF types as deprecated/unavailable.

The Clang importer generally imports a CF type under two names, one
with "Ref" and one without, which is needlessly redundant. Mark the
"Ref" versions as deprecated (with a rename to the non-"Ref" version)
now as a migration step toward removing them entirely (gated by
-enable-omit-needless-words). Fixes rdar://problem/16888940.