I see three MulticastSocket tests failing on Aix:

java/net/MulticastSocket/JoinLeave.java
java/net/MulticastSocket/SetGetNetworkInterfaceTest.java
java/net/MulticastSocket/Test.java

They all throw the same exception:

---------System.out:(1/41)---------
Joining: /224.80.80.80 on name:en0 (en0)
---------System.err:(32/2347)---------
java.io.UncheckedIOException: java.net.SocketException: Can't assign requested address (Error setting socket option)
at JoinLeave.joinLeave(JoinLeave.java:74)
at JoinLeave.lambda$main$0(JoinLeave.java:61)
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
at java.base/java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1603)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
at JoinLeave.main(JoinLeave.java:61)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at com.sun.javatest.regtest.agent.MainActionHelper$SameVMRunnable.run(MainActionHelper.java:229)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.net.SocketException: Can't assign requested address (Error setting socket option)
at java.base/java.net.PlainDatagramSocketImpl.socketSetOption0(Native Method)
at java.base/java.net.PlainDatagramSocketImpl.socketSetOption(PlainDatagramSocketImpl.java:91)
at java.base/java.net.AbstractPlainDatagramSocketImpl.setOption(AbstractPlainDatagramSocketImpl.java:352)
at java.base/java.net.MulticastSocket.setNetworkInterface(MulticastSocket.java:560)
at JoinLeave.joinLeave(JoinLeave.java:69)
... 19 more

I see the same issue with OpenJ9 10 downloaded from AdoptOpenJdk:

openjdk version "10.0.1-adoptopenjdk" 2018-04-17
OpenJDK Runtime Environment (build 10.0.1-adoptopenjdk+10)
Eclipse OpenJ9 VM (build master-f7532ad, JRE 10 AIX ppc64-64-Bit Compressed References 20180712_247 (JIT enabled, AOT enabled)
OpenJ9 - f7532ad
OMR - 931f720
JCL - e180ae0 based on jdk-10.0.1+10)

We run the test on AIX 7.1.