test_gengrid: Added more test cases to reveal bugs in horizontal mode.
test_gengrid: Added more test cases to reveal bugs in horizontal mode.

Summary:
- Added focus highlight, focus animation & horizontal mode option to enable/disable.
- Removed unnecessary frame and label from test code.

Test Plan: elementary_test -to "Gengrid Focus"

Reviewers: seoz, raster

CC: seoz, nirajkr

Differential Revision: https://phab.enlightenment.org/D683

rvandegrift/elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,tasn/elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,rvandegrift/elementary