tests/subsurface-shot: hardcode reference image names

Using the test name for the reference images will stop working when the new
test harness starts using fixtures. Fixtures allow running the same tests in
varying environments, so the test results file names will include fixture
index. However the reference images will remain the same for all fixtures.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

tests/subsurface-shot-test.c

@@ -176,7 +176,6 @@ surface_commit_color(struct client *client, struct wl_surface *surface,
 
 TEST(subsurface_z_order)
 {
-	const char *test_name = get_test_name();
 	struct client *client;
 	struct wl_subcompositor *subco;
 	struct buffer *bufs[5] = { 0 };
@@ -207,7 +206,7 @@ TEST(subsurface_z_order)
 	bufs[0] = surface_commit_color(client, surf[0], &red, 100, 100);
 	/* sub[0] is not used */
 
-	fail += check_screen(client, test_name, 0, &clip, 0);
+	fail += check_screen(client, "subsurface_z_order", 0, &clip, 0);
 
 	/* create a blue sub-surface above red */
 	surf[1] = wl_compositor_create_surface(client->wl_compositor);
@@ -217,7 +216,7 @@ TEST(subsurface_z_order)
 	wl_subsurface_set_position(sub[1], 20, 20);
 	wl_surface_commit(surf[0]);
 
-	fail += check_screen(client, test_name, 1, &clip, 1);
+	fail += check_screen(client, "subsurface_z_order", 1, &clip, 1);
 
 	/* create a cyan sub-surface above blue */
 	surf[2] = wl_compositor_create_surface(client->wl_compositor);
@@ -228,7 +227,7 @@ TEST(subsurface_z_order)
 	wl_surface_commit(surf[1]);
 	wl_surface_commit(surf[0]);
 
-	fail += check_screen(client, test_name, 2, &clip, 2);
+	fail += check_screen(client, "subsurface_z_order", 2, &clip, 2);
 
 	/* create a green sub-surface above blue, sibling to cyan */
 	surf[3] = wl_compositor_create_surface(client->wl_compositor);
@@ -239,13 +238,13 @@ TEST(subsurface_z_order)
 	wl_surface_commit(surf[1]);
 	wl_surface_commit(surf[0]);
 
-	fail += check_screen(client, test_name, 3, &clip, 3);
+	fail += check_screen(client, "subsurface_z_order", 3, &clip, 3);
 
 	/* stack blue below red, which brings also cyan and green below red */
 	wl_subsurface_place_below(sub[1], surf[0]);
 	wl_surface_commit(surf[0]);
 
-	fail += check_screen(client, test_name, 4, &clip, 4);
+	fail += check_screen(client, "subsurface_z_order", 4, &clip, 4);
 
 	assert(fail == 0);