RFR: 8233373: hs_err should report the location of JFR files

[Yasumasa Suenaga]

Hi all,

Please review this change:

   JBS: https://bugs.openjdk.java.net/browse/JDK-8233373
   webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8233373/webrev.00/

Since JFR Event Streaming (JEP 349), JFR file in the repository would keep most recently data.
It is very useful for postmortem analysis. So it helps JVM engineer to acquire them from the user if hs_err log points it.


Examples:

* Show JFR repository path:
```
# JFR files might be saved in the repository:
# /tmp/2019_11_01_11_09_30_3529
```

* Show emergency dump path
```
# JFR data is saved as:
# /home/ysuenaga/github/garakuta/NativeSEGV/hs_err_pid3807.jfr
```


This webrev passed all tests on submit repo (mach5-one-ysuenaga-JDK-8233373-20191101-0248-6329106)


Thanks,

Yasumasa