The second jtreg added as new build tool which could be sed with --with-jtregMW. It is used to run tests only when MAIN_WRAPPER is defined.

The standard execution is not affected, and jtregMW is not needed to be set.

The MAIN_WRAPPER make property was added.
It could be set to Virtual, Kernel to execute tests in threads.
The ProcessTols also use the "main.wrapper" to execute spawned processes with virtual thread as wrapper for main.