ivi-shell: implement surface_on_many_layer test

A surface can be added to many layers.
This test is implemented to test this use-case
and the correct behaviour of get_layers_under_surface
API.

Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/tests/ivi_layout-test.c b/tests/ivi_layout-test.c
index b775abe..4814e2d 100644
--- a/tests/ivi_layout-test.c
+++ b/tests/ivi_layout-test.c
@@ -199,6 +199,7 @@
 	"surface_bad_opacity",
 	"surface_properties_changed_notification",
 	"surface_bad_properties_changed_notification",
+	"surface_on_many_layer",
 };
 
 const char * const surface_property_commit_changes_test_names[] = {