tests: benchmarks: multicore: idle_counter: align with test sequence

Interleave active and sleep states.

Signed-off-by: Piotr Kosycarz <[email protected]>

Author: nordic-piks

tests/benchmarks/multicore/idle_counter/src/main.c

@@ -122,9 +122,7 @@ int main(void)
 		start_time = start_timer(counter_dev);
 		k_msleep(100);
 		verify_timer(start_time);
-		ret = gpio_pin_set_dt(&led, 1);
-		__ASSERT(ret == 0, "Unable to turn on LED");
-		k_msleep(100);
+		k_busy_wait(100000);
 	}
 
 	return 0;