[jdk17u-dev] RFR: 8309527: Improve test proxy performance

[Goetz Lindenmaier]

I backport this for parity with 17.0.12-oracle.

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Commit messages:
 - Backport fadcd6501879af40360b217d2f76ab86a6f55d27

Changes: https://git.openjdk.org/jdk17u-dev/pull/2388/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=2388&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309527
  Stats: 29 lines in 5 files changed: 5 ins; 0 del; 24 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/2388.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/2388/head:pull/2388

PR: https://git.openjdk.org/jdk17u-dev/pull/2388