[MC-122355] Crash on breaking banner: java.lang.ClassCastException: arw cannot be cast to aru

Occurred on old/updated world. Save on disk. No longer in the Select World list.

Crash report

17w47b: crash-2017-11-23_12.40.02-server.txt

Description: Ticking player

java.lang.ClassCastException: arw cannot be cast to aru
	at ayn.l(SourceFile:220)
	at ayn.j(SourceFile:207)
	at aru.a(SourceFile:75)
	at qo.b(SourceFile:235)
	at qo.a(SourceFile:92)
	at qn.H_(SourceFile:307)
	at aqc.a(SourceFile:1564)
	at ql.a(SourceFile:704)
	at aqc.h(SourceFile:1540)
	at ql.l(SourceFile:560)
	at aqc.k(SourceFile:1405)
	at ql.k(SourceFile:537)
	at net.minecraft.server.MinecraftServer.w(SourceFile:656)
	at net.minecraft.server.MinecraftServer.v(SourceFile:584)
	at ckv.v(SourceFile:152)
	at net.minecraft.server.MinecraftServer.run(SourceFile:489)
	at java.lang.Thread.run(Unknown Source)