[jdk25u] RFR: 8279005: sun/tools/jstat tests do not check for test case exit codes after JDK-8245129

[Paul Hohensee]

Test-only backport to fix jstat tests. Modified jstat tests (test/jdk/sun/tools/jstat/*) pass.

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Commit messages:
 - Backport c90c31b07ef64eca65be5018a7757b960552f88a

Changes: https://git.openjdk.org/jdk25u/pull/121/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u&pr=121&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8279005
  Stats: 76 lines in 16 files changed: 60 ins; 0 del; 16 mod
  Patch: https://git.openjdk.org/jdk25u/pull/121.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u.git pull/121/head:pull/121

PR: https://git.openjdk.org/jdk25u/pull/121