[jdk8u-dev] RFR: 8240235: jdk.test.lib.util.JarUtils updates jar files incorrectly

[Roman Marchenko]

This is backport of "8240235: jdk.test.lib.util.JarUtils updates jar files incorrectly", needed for backporting "8309841: Jarsigner should print a warning if an entry is removed"

Original patch does not apply cleanly to jdk8, fixed minor conflict as `public static void updateJarFile(Path jarfile, Path dir, Path... files)` doesn't exist in jdk8.

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Commit messages:
 - Backport 2a791467919c9df9869e6fe1e57df0a5caa90d8f

Changes: https://git.openjdk.org/jdk8u-dev/pull/640/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=640&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8240235
  Stats: 15 lines in 1 file changed: 13 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/640.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/640/head:pull/640

PR: https://git.openjdk.org/jdk8u-dev/pull/640