quorum.auth.MiniKdcTest.testKerberosLogin failing with NPE on java 9

javax.security.auth.login.LoginException: java.lang.NullPointerException: invalid null input(s)
	at java.base/java.util.Objects.requireNonNull(Objects.java:246)
	at java.base/javax.security.auth.Subject$SecureSet.remove(Subject.java:1172)
	at java.base/java.util.Collections$SynchronizedCollection.remove(Collections.java:2039)
	at jdk.security.auth/com.sun.security.auth.module.Krb5LoginModule.logout(Krb5LoginModule.java:1193)
	at java.base/javax.security.auth.login.LoginContext.invoke(LoginContext.java:732)
	at java.base/javax.security.auth.login.LoginContext.access$000(LoginContext.java:194)
	at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:665)
	at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:663)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/javax.security.auth.login.LoginContext.invokePriv(LoginContext.java:663)
	at java.base/javax.security.auth.login.LoginContext.logout(LoginContext.java:613)
	at org.apache.zookeeper.server.quorum.auth.MiniKdcTest.testKerberosLogin(MiniKdcTest.java:179)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at org.apache.zookeeper.JUnit4ZKTestRunner$LoggedInvokeMethod.evaluate(JUnit4ZKTestRunner.java:55)

	at java.base/javax.security.auth.login.LoginContext.invoke(LoginContext.java:821)
	at java.base/javax.security.auth.login.LoginContext.access$000(LoginContext.java:194)
	at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:665)
	at java.base/javax.security.auth.login.LoginContext$4.run(LoginContext.java:663)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/javax.security.auth.login.LoginContext.invokePriv(LoginContext.java:663)
	at java.base/javax.security.auth.login.LoginContext.logout(LoginContext.java:613)
	at org.apache.zookeeper.server.quorum.auth.MiniKdcTest.testKerberosLogin(MiniKdcTest.java:179)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at org.apache.zookeeper.JUnit4ZKTestRunner$LoggedInvokeMethod.evaluate(JUnit4ZKTestRunner.java:55)