ERZ1's moving platforms accelerate the player way too fast

First reported on GitHub: https://github.com/STJr/SRB2/issues/507

Happens in latest next, doesn't happen in 2.2.10.

changed milestone to %2.2.11

added Bug Regression UDMF labels

mentioned in merge request !1813 (merged)

closed with merge request !1813 (merged)

mentioned in commit ac7f983c