util: Remove a bunch of unused debug topics

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1465

src/core/util.c

@@ -287,8 +287,6 @@ topic_name (MetaDebugTopic topic)
       return "WORKAREA";
     case META_DEBUG_STACK:
       return "STACK";
-    case META_DEBUG_THEMES:
-      return "THEMES";
     case META_DEBUG_SM:
       return "SM";
     case META_DEBUG_EVENTS:
@@ -303,14 +301,10 @@ topic_name (MetaDebugTopic topic)
       return "GEOMETRY";
     case META_DEBUG_PING:
       return "PING";
-    case META_DEBUG_XINERAMA:
-      return "XINERAMA";
     case META_DEBUG_KEYBINDINGS:
       return "KEYBINDINGS";
     case META_DEBUG_SYNC:
       return "SYNC";
-    case META_DEBUG_ERRORS:
-      return "ERRORS";
     case META_DEBUG_STARTUP:
       return "STARTUP";
     case META_DEBUG_PREFS:
@@ -321,8 +315,6 @@ topic_name (MetaDebugTopic topic)
       return "RESIZING";
     case META_DEBUG_SHAPES:
       return "SHAPES";
-    case META_DEBUG_COMPOSITOR:
-      return "COMPOSITOR";
     case META_DEBUG_EDGE_RESISTANCE:
       return "EDGE_RESISTANCE";
     case META_DEBUG_DBUS: