[jdk21u-dev] RFR: 8346871: Improve robustness of java/util/zip/EntryCount64k.java test

[Goetz Lindenmaier]

I backport this for parity with 21.0.8-oracle.

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Commit messages:
 - Backport 24c5ff7ba58cb7cf93df07f81484cd8fae60e31e

Changes: https://git.openjdk.org/jdk21u-dev/pull/1884/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1884&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346871
  Stats: 9 lines in 1 file changed: 7 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1884.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1884/head:pull/1884

PR: https://git.openjdk.org/jdk21u-dev/pull/1884