RFR: 7904069: Fix counters in testng.txt report

[Christian Stein]

Please review this change to fix counters in `testng.txt` report files.

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Commit messages:
 - 7904069: Fix counters in testng.txt report

Changes: https://git.openjdk.org/jtreg/pull/280/files
  Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=280&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7904069
  Stats: 13 lines in 2 files changed: 2 ins; 4 del; 7 mod
  Patch: https://git.openjdk.org/jtreg/pull/280.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/280/head:pull/280

PR: https://git.openjdk.org/jtreg/pull/280