Don't reset non replayed timestamps
Quoting the last commit:
x11: Limit touch replay pointer events to when replaying When a touch sequence was rejected, the emulated pointer events would be replayed with old timestamps. This caused issues with grabs as they would be ignored due to being too old. This was mitigated by making sure device event timestamps never travelled back in time by tempering with any event that had a timestamp seemingly in the past. This failed when the most recent timestamp that had been received were much older than the timestamp of the new event. This could for example happen when a session was left not interacted with for 40+ days or so; when interacted with again, as any new timestamp would according to XSERVER_TIME_IS_BEFORE() still be in the past compared to the "most recent" one. The effect is that we'd always use the `latest_evtime` for all new device events without ever updating it. The end result of this was that passive grabs would become active when interacted with, but would then newer be released, as the timestamps to XIAllowEvents() would out of date, resulting in the desktop effectively freezing, as the Shell would have an active pointer grab. To avoid the situation where we get stuck with an old `latest_evtime` timestamp, limit the tempering with device event timestamp to 1) only pointer events, and 2) only during the replay sequence. The second part is implemented by sending an asynchronous message via the X server after rejecting a touch sequence, only potentially tempering with the device event timestamps until the reply. This should avoid the stuck timestamp as in those situations, we'll always have a relatively up to date `latest_evtime` meaning XSERVER_TIME_IS_BEFORE() will not get confused.