RFR: 8333344: JMX attaching of Subject does not work when security manager not allowed

[Kevin Walls]

JMX uses APIs related to the Security Mananger which are deprecated.  Use of AccessControlContext will be removed when Security Manager is removed.

Until then, updates are needed to not require setting  -Djava.security.manager=allow to use JMX authentication.

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Commit messages:
 - Additional test combination, old getSubject call with sm=allow
 - Test updates
 - whitespace
 - Merge remote-tracking branch 'upstream/master' into 8333344_JMX_Subject
 - 8333344: JMX attaching of Subject does not work when security manager not allowed

Changes: https://git.openjdk.org/jdk/pull/19624/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19624&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8333344
  Stats: 160 lines in 19 files changed: 109 ins; 10 del; 41 mod
  Patch: https://git.openjdk.org/jdk/pull/19624.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19624/head:pull/19624

PR: https://git.openjdk.org/jdk/pull/19624