cogl/onscreen: Add cogl_onscreen_egl_maybe_create_timestamp_query

Move the code out of cogl_onscreen_egl_swap_buffers_with_damage, and
call the new function from callers of the former.

v2:
* Use early return if the cogl context doesn't support timestamp
  queries. (Sebastian Wick)

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3689>

src/backends/native/meta-onscreen-native.c

@@ -1305,6 +1305,8 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen  *onscreen,
                                                  rectangles,
                                                  n_rectangles);
 
+  cogl_onscreen_egl_maybe_create_timestamp_query (onscreen, frame_info);
+
   parent_class = COGL_ONSCREEN_CLASS (meta_onscreen_native_parent_class);
   parent_class->swap_buffers_with_damage (onscreen,
                                           rectangles,

src/backends/x11/nested/meta-stage-x11-nested.c

@@ -186,6 +186,8 @@ meta_stage_x11_nested_finish_frame (ClutterStageWindow *stage_window,
     }
 
   frame_info = cogl_frame_info_new (context, 0);
+  cogl_onscreen_egl_maybe_create_timestamp_query (stage_x11->onscreen,
+                                                  frame_info);
   cogl_onscreen_swap_buffers (stage_x11->onscreen, frame_info, frame);
 
   if (!clutter_frame_has_result (frame))