RFR: CODETOOLS-7903471: JMH: Add test for virtual threads executor [v4]

[Sergey Kuksenko]

> Add test for virtual thread executor

Sergey Kuksenko has updated the pull request incrementally with one additional commit since the last revision:

  fix CODETOOLS-7903476 and expand tests

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Changes:
  - all: https://git.openjdk.org/jmh/pull/103/files
  - new: https://git.openjdk.org/jmh/pull/103/files/fead59fb..5de0832f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmh&pr=103&range=03
 - incr: https://webrevs.openjdk.org/?repo=jmh&pr=103&range=02-03

  Stats: 76 lines in 4 files changed: 51 ins; 1 del; 24 mod
  Patch: https://git.openjdk.org/jmh/pull/103.diff
  Fetch: git fetch https://git.openjdk.org/jmh.git pull/103/head:pull/103

PR: https://git.openjdk.org/jmh/pull/103