Remove faulty code from T_MovePlane()

T_MovePlane()'s code block at the end makes some exceptions to supposedly handle MT_SPINFIRE, MT_SPIKE and MT_GOOP's height properly, however this exceptional handling has proven to be useless at most, and faulty in some cases. While glitch-rocketing spikes up into the air sounds hilarious, I consider the behavior to be undesirable. This merge request removes the faulty code as well as the related line_t.tagline pointer as it served no other purpose.

2.2.2:

This branch:

changed the description

changed target branch from master to next

changed title from Remove presumably useless code from T_MovePlane() to Remove faulty code from T_MovePlane()

I will note a behavior change, which involves quicksand: In 2.2.2, spikes placed on a quicksand surface will remain on a surface indefinitely until another surface comes out of the quicksand and "picks" them up, after that, the spikes will stick to said surface:

In this branch, the spikes remain on the surface of the quicksand no matter what:

CEZ1's mud spikes seem to be unaffected by this change.

added 1 commit

• 01c0797b - Remove now unused P_MobjReadyToMove().

Compare with previous version

IIRC the original code was made to fix a bug reported way back in 2.0 involving quicksand: https://mb.srb2.org/showthread.php?t=33772 (unfortunately the image no longer works, but the level in question lowered the quicksand after a boss fight against Egg Slimer, and the slimes stayed floating in midair even though the quicksand was gone; also hi I made the level)

merged

mentioned in commit 464ecc01