RFR: 8333344: JMX attaching of Subject does not work when security manager not allowed [v16]

[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.

Kevin Walls has updated the pull request incrementally with two additional commits since the last revision:

 - style update
 - whitespace

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/19624/files
  - new: https://git.openjdk.org/jdk/pull/19624/files/2f2179e7..597264b9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19624&range=15
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19624&range=14-15

  Stats: 11 lines in 2 files changed: 4 ins; 0 del; 7 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