perf($compile): don't register $destroy callbacks on element-transcluded nodes

This is a major perf win in the large table benchmark (~100ms or 9).

This cleanup is needed only for regular transclusion because only then the DOM hierarchy doesn't match scope hierarchy
(transcluded scope is a child of the parent scope and not a child of the isolate scope)

We should consider refactoring this further for the case of regular transclusion
and consider using scope events instead.