Trial Spawners will not activate/spawn mobs if gamerule "doMobSpawning" is set to "false"

Trial Spawners will not activate/spawn mobs if gamerule "doMobSpawning" is set to "false".

This is different from the behavior of normal monster spawners, which will activate/spawn mobs no matter if "doMobSpawning" is set to true or false.

Code analysis provided in this comment.