There were two edge cases in the frame waiting logic (aka manual frame
throttling or emulated vsync) which would cause the editor to stall in
one way or another:
1. Waiting right after starting the editor would cause a deadlock
between both threads until something happened in the Wayland event
queue, in turn unblocking the Wayland thread and kickstartin the whole
thing;
2. Starting the editor (and probably other long-loading stuff) without
low consumption mode would suspend the window and never commit its
surfaces, thus never signaling the compositor that we want frame events.
cbd68eb403