Enable asserts in iteration test

rerenderSelective was added back to the iteration component. Re-enable parts
of the iteration test that weren't working without this method. We should now
be verifying the whole iteration isn't destroyed and re-created when a single
item is added or destroyed.

@bug W-2108838@
@rev rjayaramappa@
Merging origin/tbliss/master-pending-enable-iteration-test into master