RFR: 8279005: sun/tools/jstat tests do not check for test case exit codes after JDK-8245129

[Paul Hohensee]

On Tue, 24 Jun 2025 13:48:02 GMT, Paul Hohensee <phh at openjdk.org> wrote:

> Please review a jstat test-only fix.
> 
> 1. Ensure that jstat tests that run more than one sub-test per test file check the result of each sub-test before continuing.
> 2. Allow '-' as a valid jstat -gcutil heap space percent occupancy field value, see lineCounts[1-4].awk. Occupancy is computed as ((capacity - used) / capacity), see src/jdk.jcmd/share/classes/sun/tools/jstat/resources/jstat_options, search for "gcutil". G1, ZGC, and Shenandoah may return zero capacity for any or all of survivor spaces, eden, old gen, metaspace, and compressed class space, leading to an occupancy result represented '-'.
> 
> Modified tests pass.

Windows GHA failures are infra-related and unrelated to this change.

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PR Comment: https://git.openjdk.org/jdk/pull/25951#issuecomment-3000612238