RFR: 7903931: Add "jtreg.ttf" property to filter tests based on test thread factory value

[Leonid Mesnik]

jtreg support test thread factory parameter that allows to execute tests by running main in virtual thread.

Currently, all incompatible tests are problemlisted. However after security manager removal the number of such tests is small.

So is it makes sense to add "jtreg.ttf" property to filter tests based on test thread factory value to allow filter out incompatible tests.

The only jtreg knows if -testThreadFactory is set so it should set corresponding property

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

Commit messages:
 - Add "jtreg.ttf" property to filter tests based on test thread factory value

Changes: https://git.openjdk.org/jtreg/pull/242/files
  Webrev: https://webrevs.openjdk.org/?repo=jtreg&pr=242&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903931
  Stats: 6 lines in 1 file changed: 5 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jtreg/pull/242.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/242/head:pull/242

PR: https://git.openjdk.org/jtreg/pull/242