test_gengrid.c: Fixed Item_Data array size for prevent buffer overflow.
test_gengrid.c: Fixed Item_Data array size for prevent buffer overflow.

Summary:
Item_Data size set as 144 before. but test_gengrid_speed function called create_gengrid function with 5000 items.
it makes crash.

@fix

Test Plan:
1. run elementary_test.
2. click Gengrid update Speed.
3. crash.

Reviewers: seoz, Hermet

Reviewed By: Hermet

Differential Revision: https://phab.enlightenment.org/D1834

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