[jdk17u-dev] RFR: 8271419: Refactor test code for modifying CDS archive contents

[Goetz Lindenmaier]

I backport this to make later test backports easier.
Resolved as later "8271707: migrate tests to use jdk.test.whitebox.WhiteBox" was already backported.

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Commit messages:
 - Backport 84f02310310293163130dde24e30563d39f1610a

Changes: https://git.openjdk.org/jdk17u-dev/pull/3445/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3445&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8271419
  Stats: 628 lines in 2 files changed: 330 ins; 280 del; 18 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3445.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3445/head:pull/3445

PR: https://git.openjdk.org/jdk17u-dev/pull/3445