perf(jqLite): don't use reflection to access expandoId

Since we allow only one copy of Angular to be loaded at a time it doesn't
make much sense randomly generate the expando property name and then be
forced to use slow reflective calles to retrieve the IDs.
perf(jqLite): optimize element dealocation

Iterate only over elements and not nodes since we don't attach data or handlers
to text/comment nodes.