RFR: 8307305: Update debugger tests to support JTREG_TEST_THREAD_FACTORY mode [v2]

[Leonid Mesnik]

> The debugger tests might start all debugee using virtual threads when property "main.wrapper" is set.
> However, the new mode JTREG_TEST_THREAD_FACTORY do the same thing. The only difference is that it use predefined problemlist names and doesn't set property "main.wrapper" as a part of jtreg properties. So nsk wrapper should set it additionally.

Leonid Mesnik has updated the pull request incrementally with one additional commit since the last revision:

  Fixed main.wrapper property usage.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13763/files
  - new: https://git.openjdk.org/jdk/pull/13763/files/b5f06cb2..8c000319

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13763&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13763&range=00-01

  Stats: 2 lines in 2 files changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/13763.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13763/head:pull/13763

PR: https://git.openjdk.org/jdk/pull/13763