RFR: 8342811: java/net/httpclient/PlainProxyConnectionTest.java failed: Unexpected connection count: 5

[Volkan Yazıcı]

This PR introduces the following changes addressing intermittent `PlainProxyConnectionTest` failures reported in [JDK-8342811](https://bugs.openjdk.org/browse/JDK-8342811):

* Increase logging verbosity to aid in troubleshooting (if the failure happens to pop up again)
* Add salt to the used HTTP server path to decrease the chances of parallel running tests from interfering

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Commit messages:
 - Remove redundant module declarations
 - Fix copyright year
 - 8342811: Increase PlainProxyConnectionTest logging verbosity

Changes: https://git.openjdk.org/jdk/pull/22003/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22003&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342811
  Stats: 22 lines in 1 file changed: 16 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/22003.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22003/head:pull/22003

PR: https://git.openjdk.org/jdk/pull/22003