[MC-203332] Using "fancy_trunk_placer" with a block that doesn't use an axis block state crashes the game

When creating a custom tree feature that uses the fancy_trunk_placer and a trunk block without an axis block state, the game will crash when trying to generate the feature.

The tree feature that crashed the game during generation is attached.

1.16.4-rc1: crash-2020-11-01_19.12.44-server.txt

Description: Feature placement

java.lang.IllegalArgumentException: Cannot set property cfe{name=axis, clazz=class gc$a, values=[x, y, z]} as it does not exist in Block{minecraft:air}
	at cej.a(SourceFile:114)
	at cow.a(SourceFile:121)
	at cow.a(SourceFile:92)
	at cld.a(SourceFile:127)
	at cld.a(SourceFile:163)
	at cld.a(SourceFile:37)
	at civ.a(SourceFile:55)
	at ckm.a(SourceFile:23)
	at ckm.a(SourceFile:11)
	at civ.a(SourceFile:55)
	at cjb.a(SourceFile:23)
	at cjb$$Lambda$4248/574936991.accept(Unknown Source)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
	at java.util.stream.Streams$StreamBuilderImpl.forEachRemaining(Streams.java:419)
	at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:580)
	at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:270)
	at java.util.stream.Streams$StreamBuilderImpl.forEachRemaining(Streams.java:419)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
	at cjb.a(SourceFile:22)
	at cjb.a(SourceFile:14)
	at civ.a(SourceFile:55)
	at cjb.a(SourceFile:23)
	at cjb$$Lambda$4248/574936991.accept(Unknown Source)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
	at java.util.stream.IntPipeline$4$1.accept(IntPipeline.java:250)
	at java.util.stream.Streams$RangeIntSpliterator.forEachRemaining(Streams.java:110)
	at java.util.Spliterator$OfInt.forEachRemaining(Spliterator.java:693)
	at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:512)
	at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:502)
	at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
	at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
	at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
	at cjb.a(SourceFile:22)
	at cjb.a(SourceFile:14)
	at civ.a(SourceFile:55)
	at bsv.a(SourceFile:373)
	at cfy.a(SourceFile:220)
	at cga.c(SourceFile:89)
	at cga$$Lambda$1795/846757358.doWork(Unknown Source)
	at cga.a(SourceFile:219)
	at zs.a(SourceFile:568)
	at zs$$Lambda$4225/473450621.apply(Unknown Source)
	at com.mojang.datafixers.util.Either$Left.map(Either.java:38)
	at zs.a(SourceFile:562)
	at zs$$Lambda$4210/762583078.apply(Unknown Source)
	at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:952)
	at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926)
	at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:442)
	at zu.b(SourceFile:58)
	at zu$$Lambda$4223/1925101086.run(Unknown Source)
	at aoe.e(SourceFile:94)
	at aoe.a(SourceFile:137)
	at aoe.run(SourceFile:105)
	at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1402)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1689)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)