RFR: 8344078: Remove security manager dependency in java.nio

[Brian Burkhalter]

Expunge the use of the `SecurityManager`, `AccessController`, and the like from the `java.nio` and `sun.nio` package hierarchies.

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Commit messages:
 - 8344078: Remove security manager dependency in java.nio

Changes: https://git.openjdk.org/jdk/pull/22132/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22132&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344078
  Stats: 1318 lines in 63 files changed: 9 ins; 1082 del; 227 mod
  Patch: https://git.openjdk.org/jdk/pull/22132.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22132/head:pull/22132

PR: https://git.openjdk.org/jdk/pull/22132