[jdk21u-dev] RFR: 8351567: Jar Manifest test ValueUtf8Coding produces misleading diagnostic output

[Goetz Lindenmaier]

I backport this for parity with 21.0.10-oracle.

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Commit messages:
 - Backport ffa63409884e9a2d41f5223ab5962980edbb008c

Changes: https://git.openjdk.org/jdk21u-dev/pull/2187/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2187&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351567
  Stats: 6 lines in 1 file changed: 0 ins; 4 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2187.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2187/head:pull/2187

PR: https://git.openjdk.org/jdk21u-dev/pull/2187