RFR: 8344337: SecurityManager cleanup in java.prefs moduleRemove SecMgr, etc usage from java.prefs

[Brent Christian]

Remove usages of SecurityManager, doPrivildged, and AccessController from the java.prefs module.

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Commit messages:
 - Remove SecMgr, etc usage from java.prefs

Changes: https://git.openjdk.org/jdk/pull/22252/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22252&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344337
  Stats: 243 lines in 6 files changed: 16 ins; 129 del; 98 mod
  Patch: https://git.openjdk.org/jdk/pull/22252.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22252/head:pull/22252

PR: https://git.openjdk.org/jdk/pull/22252