RFR: CODETOOLS-7902843: Fix simple test issues found by static analysis [v2]

[Aleksey Shipilev]

> SonarCloud reports multiple problems in test code. Some of them are legitimate problems that break/weaken the tests.

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Fix the tests properly, ugh
 - Merge branch 'master' into CODETOOLS-7902843-test-fixes
 - CODETOOLS-7902843: Fix simple test issues found by static analysis

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Changes:
  - all: https://git.openjdk.java.net/jcstress/pull/9/files
  - new: https://git.openjdk.java.net/jcstress/pull/9/files/96b9aab0..4a5f780b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jcstress&pr=9&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jcstress&pr=9&range=00-01

  Stats: 99 lines in 12 files changed: 80 ins; 0 del; 19 mod
  Patch: https://git.openjdk.java.net/jcstress/pull/9.diff
  Fetch: git fetch https://git.openjdk.java.net/jcstress pull/9/head:pull/9

PR: https://git.openjdk.java.net/jcstress/pull/9