RFR: 8350571: Remove mention of Tonga test suite from JMX tests

[Kevin Walls]

Trivial removal of confusing "Tonga" references in comments within a few JMX tests.

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Commit messages:
 - 8350571: Remove mention of Tonga test suite from JMX tests

Changes: https://git.openjdk.org/jdk/pull/23747/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23747&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350571
  Stats: 27 lines in 5 files changed: 0 ins; 20 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/23747.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23747/head:pull/23747

PR: https://git.openjdk.org/jdk/pull/23747