Frozen bomb drops straight down when thrown

[ztianyang]

SuperTux version: supertux2 v0.6.3-209-g70226f163 System information: Ubuntu 20.04.3

Expected behavior

Throwing frozen bomb is like throwing rocks or trampolines.

Actual behavior

Frozen bomb drops straight down when thrown.

Steps to reproduce actual behavior

Freeze a bomb with ice bullet, then throw the frozen bomb.

https://user-images.githubusercontent.com/59285502/150665633-f792a882-c2a1-4b78-bd8f-455baa8595c2.mp4

[Semphriss]

Related to #683

Many badguys can't be carried at all in frozen form, including haywires and jumpys.

[Alasdairbugs]

bombs should not be thrown like ice cubes

[ztianyang]

Fixed in nightly