RFR: JDK-8295756 Improve NonLocalRegistry Manual Test Process

[Bill Huang]

The current non local registry tests require a manual process that runs rmiregitrty on a different machine and changes the -Dregistry.host property in the source before running the tests on the local machine. This task is created to improve this manual process and provide a clearer instruction to the test engineer about the test requirement. 

Tests include: 
java/rmi/registry/nonLocalRegistry/NonLocalSkeletonTest.java 
java/rmi/registry/nonLocalRegistry/NonLocalRegistryTest.java 
javax/management/remote/nonLocalAccess/NonLocalJMXRemoteTest.java

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Commit messages:
 - Updated TEST.groups
 - JDK-8295756 Improve NonLocalRegistry Manual Test Process

Changes: https://git.openjdk.org/jdk/pull/10825/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10825&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295756
  Stats: 270 lines in 6 files changed: 235 ins; 2 del; 33 mod
  Patch: https://git.openjdk.org/jdk/pull/10825.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10825/head:pull/10825

PR: https://git.openjdk.org/jdk/pull/10825