[MC-122883] Game crash when players suicide or kill other players: java.lang.NullPointerException: Ticking entity

The bug

Killing yourself with an arrow you shot crashes the game. Also affect the splash potion of harming / potion of harming / lingering potion of harming / TNT.

Crash report

17w48a: crash-2017-12-04_20.48.29-server.txt

Description: Ticking entity

java.lang.NullPointerException: Ticking entity
	at tl.a(SourceFile:28)
	at tl.a(SourceFile:22)
	at tl.<init>(SourceFile:15)
	at tn.a(SourceFile:24)
	at tn$$Lambda$594/171755660.apply(Unknown Source)
	at java.util.Map.computeIfAbsent(Map.java:957)
	at tn.a(SourceFile:24)
	at tn.b(SourceFile:41)
	at qo.a(SourceFile:455)
	at za.a(SourceFile:848)
	at aho.a(SourceFile:888)
	at qo.a(SourceFile:525)
	at ahs.a(SourceFile:343)
	at ahs.H_(SourceFile:264)
	at ail.H_(SourceFile:98)
	at aqg.a(SourceFile:1569)
	at qm.a(SourceFile:705)
	at aqg.h(SourceFile:1545)
	at aqg.k(SourceFile:1427)
	at qm.k(SourceFile:538)
	at net.minecraft.server.MinecraftServer.w(SourceFile:660)
	at net.minecraft.server.MinecraftServer.v(SourceFile:588)
	at ckz.v(SourceFile:152)
	at net.minecraft.server.MinecraftServer.run(SourceFile:493)
	at java.lang.Thread.run(Thread.java:745)