javax/management/remote/mandatory/connection/DefaultAgentFilterTest.java fails with Port already in use

Test failed in tier6:

[TestApp{DefaultAgentFilterTest}] Error: Exception thrown by the agent : java.rmi.server.ExportException: Port already in use: 52263; nested exception is:
java.io.IOException: Stream closed
at java.base/java.io.BufferedInputStream.getBufIfOpen(BufferedInputStream.java:176)
at java.base/java.io.BufferedInputStream.read(BufferedInputStream.java:342)
at java.base/java.io.BufferedInputStream.fill(BufferedInputStream.java:252)
at java.base/java.io.BufferedInputStream.read1(BufferedInputStream.java:292)
at java.base/java.io.BufferedInputStream.read(BufferedInputStream.java:351)
at java.base/java.io.FilterInputStream.read(FilterInputStream.java:107)
at jdk.testlibrary.StreamPumper.run(StreamPumper.java:117)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at jdk.testlibrary.StreamPumper$1.run(StreamPumper.java:196)
at java.base/java.lang.Thread.run(Thread.java:834)
java.lang.RuntimeException
at DefaultAgentFilterTest$TestAppRun.start(DefaultAgentFilterTest.java:127)
at DefaultAgentFilterTest.testDefaultAgent(DefaultAgentFilterTest.java:190)
at DefaultAgentFilterTest.main(DefaultAgentFilterTest.java:242)
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.MainWrapper$MainThread.run(MainWrapper.java:115)
at java.base/java.lang.Thread.run(Thread.java:834)
Suppressed: java.io.IOException: Stream closed
at java.base/java.lang.ProcessBuilder$NullOutputStream.write(ProcessBuilder.java:442)
at java.base/java.io.OutputStream.write(OutputStream.java:157)
at java.base/java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:81)
at java.base/java.io.BufferedOutputStream.flush(BufferedOutputStream.java:142)
at DefaultAgentFilterTest$TestAppRun.stop(DefaultAgentFilterTest.java:148)
at DefaultAgentFilterTest$TestAppRun.close(DefaultAgentFilterTest.java:162)
at DefaultAgentFilterTest.testDefaultAgent(DefaultAgentFilterTest.java:189)
... 7 more

JavaTest Message: Test threw exception: java.lang.RuntimeException
JavaTest Message: shutting down test