[jdk17u-dev] RFR: 8306711: Improve diagnosis of `IntlTest` framework

[Goetz Lindenmaier]

I backport this for parity with 17.0.15-oracle.

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Commit messages:
 - Backport f3c90f0445df359a8bc03630fc5cde2843bbfef1

Changes: https://git.openjdk.org/jdk17u-dev/pull/3185/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3185&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306711
  Stats: 171 lines in 2 files changed: 68 ins; 54 del; 49 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3185.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3185/head:pull/3185

PR: https://git.openjdk.org/jdk17u-dev/pull/3185