Skip the message loop when an editor is opening

This is a bit more restrictive than the old approach that only skipped
when `effEditOpen()` got called after `effEditGetRect()`. Not sure why
the Melda plugins block indefinitely on the message loop without this
now.

src/wine-host/bridges/group.h

@@ -162,7 +162,7 @@ class GroupBridge {
      * from the same thread, this is a simple way to synchronize blocking the
      * mesage loop between the different plugin instances.
      */
-    bool should_postpone_message_loop();
+    bool should_skip_message_loop();
 
    private:
     /**