[MC-132375] Upgrading 1.12.2 world to 1.13-pre5 crashes the game

tested with 2 void superflat worlds
created world in 1.12.2
game crashes when loading in pre-5
game does not crash when upgrading from 1.12.2 to pre-4

1.13-pre5: crash-2018-06-29_14.18.21-server.txt

---- Minecraft Crash Report ----
// I just don't know what went wrong :(

Time: 29/06/18 2:18 PM
Description: Exception in server tick loop

java.lang.NullPointerException: Exception in server tick loop
	at bta.<init>(SourceFile:13)
	at btb.b(SourceFile:313)
	at btb$$Lambda$1481/889562976.apply(Unknown Source)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
	at java.util.Iterator.forEachRemaining(Iterator.java:116)
	at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
	at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
	at btb.a(SourceFile:314)
	at bnd.n(SourceFile:81)
	at sx.p(SourceFile:591)
	at sx.<init>(SourceFile:129)
	at dej.a(SourceFile:97)
	at dej.d(SourceFile:132)
	at net.minecraft.server.MinecraftServer.run(SourceFile:505)
	at java.lang.Thread.run(Thread.java:745)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- System Details --
Details:
	Minecraft Version: 1.13-pre5
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.8.0_51, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 1151100712 bytes (1097 MB) / 1603796992 bytes (1529 MB) up to 5726797824 bytes (5461 MB)
	JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx6G
	Profiler Position: N/A (disabled)
	Player Count: 0 / 8; []
	Data Packs: vanilla
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.