I propose that we remove the SpecializationStats from the oop_oop_iterate infrastructure.

This will make it easier for a future conversion of the oop_oop_iterate macros into template functions.

Some indications that this feature isn't used that much, is that it doesn't compile when turned on and the code in InstanceMirrorKlass and InstanceClassLoaderKlass both records that the calls are coming from InstanceRefKlass.