[MC-265386] Withers can't kill multiple Armour Stands at once

Steps to Reproduce:
1) Place 4 armour stands on the floor in a 2x2 shape

2) Run the command below a few times

/execute as @e[type=armor_stand] at @s run summon armor_stand ~ ~ ~

3) Stand within the armour stands

3) Run

/summon wither ~ ~10 ~

4) The Wither cannot hurt you for a long period of time since it can only kill one armour stand at a time before it reaches you