RFR: 8353545: Improve debug info for StartOptionTest

Wed Apr 2 11:12:55 UTC 2025

The `jdk/jshell/ToolProviderTest.java` is intermittently failing. It is not clear why, so this PR attempts to add some more debug info (printing all the remaining output when the output check fails), which hopefully will help to determine the cause of the failures.

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Commit messages:
 - 8353545: Improve debug info for StartOptionTest

Changes: https://git.openjdk.org/jdk/pull/24376/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24376&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353545
  Stats: 26 lines in 1 file changed: 16 ins; 0 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/24376.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24376/head:pull/24376

PR: https://git.openjdk.org/jdk/pull/24376