Currently, when this test is run on Windows Subsystem for Linux, dir is executed as an external process.
However, dir is a cmd.exe command, and dir.exe does not exist, so the test fails as shown below.

----------System.out:(0/0)----------
----------System.err:(19/2649)*----------
java.io.IOException: Cannot run program "dir" (in directory "D:\\dev\\jdk\\build\\windows-x86_64-server-release\\test-support\\jtreg_test_jdk_jdk_jfr_event_os_TestProcessStart_java\\scratch\\0\\."): CreateProcess error=2, The system cannot find the file specified