RFR: 8313174: Create fewer predictable port clashes in management tests

[Kevin Walls]

Specifically noticed on linux-aarch64, detection of port clashes by LocateRegistry.createRegistry(port) appears "racy".

Predictable port clashes can be avoided, tests that are likely to run at the same time should not choose the same port.

Why now?  The RMI related parts are obviously fairly stable these days, as are the tests themselves.
Our OS version/host mix for testing may have changed.  The problems I looked into were on ol8-aarch64.

It doesn't seem necessary to add complexities to the tests, or change LocateRegistry much at this point, when a simple change to the tests can avoid asking for so many port clashes.



test/jdk/javax/management/remote/mandatory/passwordAuthenticator/RMIPasswdAuthTest.java:            int port = 5800;  	// 5801 to 5820
test/jdk/javax/management/remote/mandatory/passwordAuthenticator/RMIAltAuthTest.java:            int port = 5800;	// 5821 to 5840
test/jdk/javax/management/remote/mandatory/socketFactories/RMISocketFactoriesTest.java:            int port = 5800;	// 5841 to 5860
test/jdk/javax/management/remote/mandatory/subjectDelegation/SubjectDelegation1Test.java:            int port = 5800;	// 5861 to 5880
test/jdk/javax/management/remote/mandatory/subjectDelegation/SubjectDelegation2Test.java:            int port = 5800;	// 5881 to 5900
test/jdk/javax/management/remote/mandatory/subjectDelegation/SubjectDelegation3Test.java:            int port = 5800;	// 5901 to 5920

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Commit messages:
 - update
 - 8313174: Create fewer predictable port clashes in management tests

Changes: https://git.openjdk.org/jdk/pull/15039/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15039&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313174
  Stats: 16 lines in 6 files changed: 0 ins; 0 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/15039.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15039/head:pull/15039

PR: https://git.openjdk.org/jdk/pull/15039