[43] Revert "clutter/frame-clock: Fix handling of equal next_presentation_time_us"

This reverts commit 1f7527bb.

Not waiting till the next refresh cycle can cause feedback loops with Wayland clients using "empty" commits for frame events - notably Firefox, but possibly many other clients as well under certain conditions.

While for Gnome 44 a more sophisticated solution is in development, lets go with a simple and tested one for Gnome 43, going back to Gnome 42 behavior, slightly increasing the chance for frame skips.

Related: gnome-shell#6137 (closed)

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See also !2823 (merged) / !2823 (comment 1656304)