RFR: CODETOOLS-7903471: JMH: Add test for virtual threads executor [v3]

[Sergey Kuksenko]

> Add test for virtual thread executor

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

  extend tests

-------------

Changes:
  - all: https://git.openjdk.org/jmh/pull/103/files
  - new: https://git.openjdk.org/jmh/pull/103/files/ea8df735..fead59fb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmh&pr=103&range=02
 - incr: https://webrevs.openjdk.org/?repo=jmh&pr=103&range=01-02

  Stats: 447 lines in 2 files changed: 239 ins; 201 del; 7 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