Add I915_EXEC_DEFAULT to list of known engines

I dropped this from the list of rings for some tests when refactoring to
a common array. Almost all of the tests should be run over the default
exec engine to ensure ABI backwards compatiblity.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

tests/gem_busy.c

@@ -233,9 +233,13 @@ igt_main
 		igt_require(has_semaphores(fd));
 	}
 
-	for (e = intel_execution_engines; e->name; e++)
+	for (e = intel_execution_engines; e->name; e++) {
+		if (e->exec_id == 0) /* default exec-id is purely symbolic */
+			continue;
+
 		igt_subtest_f("%s", e->name)
 			test_ring(fd, e->exec_id, e->flags);
+	}
 
 	igt_fixture
 		close(fd);

tests/gem_ringfill.c

@@ -212,7 +212,7 @@ igt_main
 	for (mode = modes; mode->prefix; mode++) {
 		for (e = intel_execution_engines; e->name; e++) {
 			igt_subtest_f("%s%s%s",
-				      e->exec_id || mode->flags ? "" : mode->prefix,
+				      e->exec_id || (mode->flags & ~INTERRUPTIBLE) ? "" : mode->prefix,
 				      e->name,
 				      mode->suffix)
 				run_test(fd, e->exec_id | e->flags, mode->flags);