RFR: 8289: Remove security manager related code

[Marcus Hirt]

Also fixing a deprecation.

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Commit messages:
 - Removing permission class
 - 8289: Removing security manager related code

Changes: https://git.openjdk.org/jmc/pull/640/files
  Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=640&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8289
  Stats: 93 lines in 4 files changed: 0 ins; 90 del; 3 mod
  Patch: https://git.openjdk.org/jmc/pull/640.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/640/head:pull/640

PR: https://git.openjdk.org/jmc/pull/640