RFR: 8351567: Jar Manifest test ValueUtf8Coding produces misleading diagnostic output

[Roger Riggs]

Remove misleading/invalid diagnostic output from the JAR manifest test ValueUtf8Coding.java.

The Manifest binary stream is not a well formed UTF-8 string due to the inserted continuation characters used for lines longer than 70 characters..

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Commit messages:
 - 8351567: Jar Manifest test ValueUtf8Coding produces misleading diagnostic output

Changes: https://git.openjdk.org/jdk/pull/23971/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23971&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/jdk/pull/23971.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23971/head:pull/23971

PR: https://git.openjdk.org/jdk/pull/23971