efl_ui_spec_test: make this test work

efl_ui_spec_test: make this test work

I do not know what i was thinking when i initially wrote that test.
It never worked, the test created a widget captured all elements, deleted
the widget, then checked if there are elements left that are not knon on
the canvas yet.
Not the test first captures all elements, then creates the widget, then
deletes the widget, and checks if there are more elements than expected.
This found all the fix leaks prior to this leak.

Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D10842