RFR: 8307305: Update debugger tests to support JTREG_TEST_THREAD_FACTORY mode

[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.

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Commit messages:
 - 8307305: Update debugger tests to support JTREG_TEST_THREAD_FACTORY mode

Changes: https://git.openjdk.org/jdk/pull/13763/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13763&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307305
  Stats: 2 lines in 3 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