java.util.ConcurrentModificationException when running StaticInliner

[hanseychen]

Steps to reproduce:
1.) Build the latest Cassandra using ant clean jar
2.) Obtain soot from https://soot-build.cs.uni-paderborn.de/public/origin/master/soot/soot-master/3.3.0/build/sootclasses-trunk-jar-with-dependencies.jar, and name it sootclasses-3.3.jar
3.) Run command

java -Xmx6g -cp .:sootclasses-3.3.jar soot.Main -allow-phantom-refs -process-dir ~/apps/cassandra/build/classes/main -W

Files used to reproduce:
Cassandra trunk @ the following commit:

commit 21ebba85ac4a78dc39eaaa8816e3cd2f93467552
Author: Mick Semb Wever <mck@apache.org>
Date:   Tue Sep 10 07:17:51 2019 +0200

    Update version to 4.0-alpha2

Soot version:

3.3.0

Java version:

$ java -version
openjdk version "1.8.0_222"
OpenJDK Runtime Environment (build 1.8.0_222-8u222-b10-1ubuntu1~16.04.1-b10)
OpenJDK 64-Bit Server VM (build 25.222-b10, mixed mode)

Command line:

-allow-phantom-refs -process-dir /home/hansey/apps/cassandra/build/classes/main -W

Max Memory:

5461MB

Stack trace:

java.util.ConcurrentModificationException
	at soot.util.HashChain$LinkIterator.hasNext(HashChain.java:563)
	at soot.jimple.toolkits.invoke.StaticInliner.computeAverageMethodSizeAndSaveOriginalSizes(StaticInliner.java:193)
	at soot.jimple.toolkits.invoke.StaticInliner.internalTransform(StaticInliner.java:87)
	at soot.SceneTransformer.transform(SceneTransformer.java:36)
	at soot.Transform.apply(Transform.java:102)
	at soot.ScenePack.internalApply(ScenePack.java:35)
	at soot.Pack.apply(Pack.java:117)
	at soot.PackManager.runWholeProgramPacks(PackManager.java:613)
	at soot.PackManager.runPacksNormally(PackManager.java:495)
	at soot.PackManager.runPacks(PackManager.java:419)
	at soot.Main.run(Main.java:269)
	at soot.Main.main(Main.java:141)