Ws-cleanup plugin: PCT test fails when running with JDK11

The PCT build for this plugin with JDK 11 fails with the errors below.  The full log is attached.

[ERROR] Errors:
[ERROR] hudson.plugins.ws_cleanup.CleanupPowermockTest.initializationError(hudson.plugins.ws_cleanup.CleanupPowermockTest)
[ERROR] Run 1: CleanupPowermockTest.initializationError » Objenesis java.lang.reflect.Invocat...
[ERROR] Run 2: CleanupPowermockTest.initializationError » Objenesis java.lang.reflect.Invocat...
[ERROR] Run 3: CleanupPowermockTest.initializationError » Objenesis java.lang.reflect.Invocat...
[ERROR] Run 4: CleanupPowermockTest.initializationError » Objenesis java.lang.reflect.Invocat...
[ERROR] Run 5: CleanupPowermockTest.initializationError » Objenesis java.lang.reflect.Invocat...
[INFO]
[ERROR] hudson.plugins.ws_cleanup.CleanupTest.doNotFailToWipeoutWhenRenameFails(hudson.plugins.ws_cleanup.CleanupTest)
[ERROR] Run 1: CleanupTest.doNotFailToWipeoutWhenRenameFails:182 » AccessDenied /var/folders/...
[ERROR] Run 2: CleanupTest.doNotFailToWipeoutWhenRenameFails:182 » AccessDenied /var/folders/...
[ERROR] Run 3: CleanupTest.doNotFailToWipeoutWhenRenameFails:182 » AccessDenied /var/folders/...
[ERROR] Run 4: CleanupTest.doNotFailToWipeoutWhenRenameFails:182 » AccessDenied /var/folders/...
[ERROR] Run 5: CleanupTest.doNotFailToWipeoutWhenRenameFails:182 » AccessDenied /var/folders/...
[INFO]
[ERROR] org.junit.runner.manipulation.Filter.initializationError(org.junit.runner.manipulation.Filter)
[ERROR] Run 1: Filter.initializationError » No tests found matching Method testPluginActive(...
[ERROR] Run 2: Filter.initializationError » No runnable methods
[ERROR] Run 3: Filter.initializationError » No runnable methods
[ERROR] Run 4: Filter.initializationError » No runnable methods
[INFO]
[ERROR] PluginAutomaticTestBuilder$OtherTests.testPluginActive:99 Plugin bouncycastle...
[INFO]
[ERROR] Tests run: 43, Failures: 1, Errors: 4, Skipped: 0
[INFO]