ABI: repair the build after swiftlang#40927

This fixes the build on Windows by fixing the template code.  The
template type was not qualified and caused an ambiguity in the name
resolution with the local typename and the previously declared
namespaced name.

Author: compnerd

include/swift/ABI/Metadata.h

@@ -1108,7 +1108,7 @@ struct TargetAnyClassMetadataObjCInterop
   using StoredSize = typename Runtime::StoredSize;
 
   using TargetClassMetadataObjCInterop =
-      TargetClassMetadata<Runtime, TargetAnyClassMetadataObjCInterop<Runtime>>;
+      swift::TargetClassMetadata<Runtime, TargetAnyClassMetadataObjCInterop<Runtime>>;
 
   constexpr TargetAnyClassMetadataObjCInterop(
       TargetAnyClassMetadataObjCInterop<Runtime> *isa,