[jdk11u-dev] RFR: 8331063: Some HttpClient tests don't report leaks

[Amos Shi]

Backport of [JDK-8331063](https://bugs.openjdk.org/browse/JDK-8331063)
- This

Testing
- Local: Test passed on `MacOS 14.5`
  - `ForbiddenHeadTest.java`: Test results: passed: 1
  - `ProxySelectorTest.java`: Test results: passed: 1
- Pipeline: 
- Testing Machine:

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Commit messages:
 - Backport e4ed7ced75c53cf5ff40c5dae4830b1ee2589802

Changes: https://git.openjdk.org/jdk11u-dev/pull/2797/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2797&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331063
  Stats: 30 lines in 2 files changed: 7 ins; 0 del; 23 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2797.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2797/head:pull/2797

PR: https://git.openjdk.org/jdk11u-dev/pull/2797