Upgrade ReceiveISA.java test to be resilient to failure due to stray packets and interference

The following test failed in the JDK15 CI:

java/nio/channels/DatagramChannel/ReceiveISA.java

Here's a snippet from the log file:

#section:main
----------messages:(5/150)----------
command: main ReceiveISA
reason: Assumed action based on file name: run main ReceiveISA
Mode: agentvm
Agent id: 20
elapsed time (seconds): 0.02
----------configuration:(11/942)*----------
Boot Layer
  class path: C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.1\\b01\\bundles\\jtreg_bin-5.1.zip\\jtreg\\lib\\javatest.jar
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.1\\b01\\bundles\\jtreg_bin-5.1.zip\\jtreg\\lib\\jtreg.jar
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.1\\b01\\bundles\\jtreg_bin-5.1.zip\\jtreg\\lib\\junit.jar
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jtreg\\5.1\\b01\\bundles\\jtreg_bin-5.1.zip\\jtreg\\lib\\testng.jar
  patch: java.base T:\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part2\\patches\\java.base

Test Layer
  class path: T:\\testoutput\\test-support\\jtreg_open_test_jdk_tier2_part2\\classes\\6\\java\\nio\\channels\\DatagramChannel\\ReceiveISA.d
              C:\\ade\\mesos\\work_dir\\jib-master\\install\\jdk-15+33-1543\\src.full\\open\\test\\jdk\\java\\nio\\channels\\DatagramChannel

----------rerun:(35/4236)*----------

<snip>

----------System.out:(3/99)----------
received /100.101.197.141:57414
received /100.101.197.141:57413
received /100.101.197.141:57413
----------System.err:(12/728)----------
java.lang.Exception: Source address for packets 1 & 2 should be equal
at ReceiveISA.main(ReceiveISA.java:80)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:298)
at java.base/java.lang.Thread.run(Thread.java:832)

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

result: Failed. Execution failed: `main' threw exception: java.lang.Exception: Source address for packets 1 & 2 should be equal


test result: Failed. Execution failed: `main' threw exception: java.lang.Exception: Source address for packets 1 & 2 should be equal

Since this is a Tier2 failure, I'm starting this bug at P3.