[MC-139313] Ascending and descending simultaneously in lava while flying in creative mode causes the player to float upwards

When you try to fly up and down at the same time (space and shift) in lava, you float upwards instead of staying put like you currently do in water.

Linked issues

gaspoweredpick 2018-11-13T04:11:18Z

Relates to MC-64163

gaspoweredpick 2019-06-14T10:05:59Z

This now only happens in creative mode in 1.14.3-pre3

gaspoweredpick 2020-08-03T06:29:40Z

Can no longer reproduce in creative or spectator in 1.16.1 or 1.16.2 release candidate 1.

Appears to have been fixed in 1.16-pre3 (same version MC-183018 was fixed in). Tested in creative mode; reproduced in 1.16-pre2 but not 1.16-pre3.