efl: short-circuit test if wl_display connection fails

Force the test to abort early if ecore_wl_init fails to make
a connection to the wl_display.  For example, if a test causes
the compositor to crash, then this short-circuit prevents other
tests from continuing and potentially getting stuck waiting for
a test timeout to occur.

Signed-off-by: U. Artie Eoff <ullysses.a.eoff@intel.com>