layers: GH1592, Fix unique_objects DebugMarker Ext

CodeGen ignored these APIs as they contain handles which are embedded
in a structure and aliased. Added manual coverage.

Change-Id: I81cf1945981a8e0b69966a9d0e190e49ff728ea8
diff --git a/scripts/unique_objects_generator.py b/scripts/unique_objects_generator.py
index bafb7ae..a6dae64 100644
--- a/scripts/unique_objects_generator.py
+++ b/scripts/unique_objects_generator.py
@@ -144,6 +144,8 @@
             'vkDestroyDescriptorUpdateTemplateKHR',
             'vkUpdateDescriptorSetWithTemplateKHR',
             'vkCmdPushDescriptorSetWithTemplateKHR',
+            'vkDebugMarkerSetObjectTagEXT',
+            'vkDebugMarkerSetObjectNameEXT',
             ]
         # Commands shadowed by interface functions and are not implemented
         self.interface_functions = [