RFR: 8315362: NMT: summary diff reports threads count incorrectly

[Evgeny Ignatenko]

8315362: NMT: summary diff reports threads count incorrectly

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Commit messages:
 - Resolve conflicts
 - 8315362: NMT: summary diff reports threads count incorrectly

Changes: https://git.openjdk.org/jdk/pull/15490/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15490&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315362
  Stats: 91 lines in 3 files changed: 87 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/15490.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15490/head:pull/15490

PR: https://git.openjdk.org/jdk/pull/15490