tests/elm_focus: explicitly set widgets to expand+fill in test

Summary:
some widgets do not create a minimum size for themselves, resulting in
a 0x0 layout which can affect tests that rely on object visibility to
succeed without errors
Depends on D9007

Reviewers: bu5hm4n

Reviewed By: bu5hm4n

Subscribers: cedric, reviewers, committers

Tags: efl

Differential Revision: https://phab.enlightenment.org/D9008