RFR: 8344219: Remove calls to SecurityManager and doPrivileged in java.net.SocksSocketImpl after JEP 486 integration [v3]

[Volkan Yazıcı]

> Removes `SecurityManager` et al. from `SocksSocketImpl`. `tier2` and `tier3` tests have passed – CI run links are available in the ticket.

Volkan Yazıcı has updated the pull request incrementally with one additional commit since the last revision:

  Revert to using a synchronized method to perform the connection

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22271/files
  - new: https://git.openjdk.org/jdk/pull/22271/files/5afb92b9..3b06bb14

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22271&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22271&range=01-02

  Stats: 13 lines in 1 file changed: 9 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/22271.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22271/head:pull/22271

PR: https://git.openjdk.org/jdk/pull/22271