tests: schedule_api: skip test assert if COVERAGE

This test case is so timing sensitive that gathering code
coverage data screws up the results.

Since this is an abnormal execution environment anyway,
just skip the assertions if CONFIG_COVERAGE=y.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

tests/kernel/sched/schedule_api/src/test_sched_timeslice_reset.c

@@ -70,8 +70,16 @@ static void thread_tslice(void *p1, void *p2, void *p3)
 	#endif
 
 	/** TESTPOINT: timeslice should be reset for each preemptive thread*/
-	zassert_true(t >= expected_slice_min, NULL);
-	zassert_true(t <= expected_slice_max, NULL);
+#ifndef CONFIG_COVERAGE
+	zassert_true(t >= expected_slice_min,
+		     "timeslice too small, expected %u got %u",
+		     expected_slice_min, t);
+	zassert_true(t <= expected_slice_max,
+		     "timeslice too big, expected %u got %u",
+		     expected_slice_max, t);
+#else
+	(void)t;
+#endif /* CONFIG_COVERAGE */
 	thread_idx = (thread_idx + 1) % NUM_THREAD;
 
 	/* Keep the current thread busy for more than one slice, even though,