RFR: 8283092: JMX subclass permission check redundant with strong encapsulation [v2]

[Kevin Walls]

> Removing permission checks which, in the presence of a Security Manager, would check for a RuntimePermission "className.subclass".  This was to prevent subclassing these classes, but is no longer necessary with strong encapsulation from modules.

Kevin Walls has updated the pull request incrementally with one additional commit since the last revision:

  Test update

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7827/files
  - new: https://git.openjdk.java.net/jdk/pull/7827/files/a6d05f73..98f1577d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7827&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7827&range=00-01

  Stats: 71 lines in 1 file changed: 28 ins; 11 del; 32 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7827.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7827/head:pull/7827

PR: https://git.openjdk.java.net/jdk/pull/7827