[8u] RFR: 8213448: [TESTBUG] enhance jfr/jvm/TestDumpOnCrash

[Ekaterina Vergizova]

Hello,
I would like to backport JFR test only issue 8213448 to 8u as a prerequisite for JDK-8217362 backport.

JBS: https://bugs.openjdk.java.net/browse/JDK-8213448
Original patch: https://hg.openjdk.java.net/jdk/jdk/rev/f0af7fd0c9ca
Webrev for 8u: https://cr.openjdk.java.net/~apetushkov/jfr_backports_katya/8213448/webrev.00/

The patch doesn't apply cleanly due to the different context (Crasher.main method content, ProcessTools.createJavaProcessBuilder parameters), reapplied manually.
Then I made the following modifications to adjust the test to 8u:
- ProcessHandle.current().pid() calls are replaced by ProcessTools.getProcessId()
- Process.pid() call is replaced by obtaining pid from the process output due to lack of Process.pid() method in 8u.

The affected test passed successfully on Linux and Windows.

Thanks,
Ekaterina