Arrows of harming/healing do not stack with bow damage

Arrows of harming (or healing for undead mobs) do not stack with bow damage, what ever damage source does more damage overrides the other damage source.

If the harming effect does more damage then the bow would with normal arrows then only the damage from the harming effect is applied.

If the bow damage with normal arrows is more damage then the harming effect then only the bow damage is applied.

This is determined before damage reduction, so a power V bow fully drawn and using an arrow of harming (instant damage II) against a target in diamond armor (just for example) will only do about 2 hearts of damage. If instead the bow is hardly drawn at all then it will do 6 hearts of damage, the damage from the instant damage II effect.

Demonstration: https://youtu.be/9OW9YXTFnTo

Steps to reproduce:

1. /give @s crossbow
2. /give @s minecraft:tipped_arrow{Potion:"minecraft:strong_harming"} 32
3. /summon minecraft:blaze ~ ~ ~ {Health:16,NoAI:1b}
4. Shoot the blaze with the crossbow
5. /data get entity @e[type=blaze,limit=1,sort=nearest] Health

Expected behavior: The blaze would have died, having taken 7-11 damage from the arrow plus 12 from the instant damage effect for a total of 19-23 damage.

Observed behavior: The blaze survives with 4 health; the arrow damage was disregarded.

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Reason: see MC-111626.