RFR: 8244508: JFR: FlightRecorderOptions reset date format

[Erik Gahlin]

Hi,

Could I have review of a date formatting problem when using 
-XX:FlightRecorderOption.

To prevent DCmdConfigure to load classes related to date formatting 
early during startup a verbose flag is added. This has an additional 
benefit of reducing the startup time since native code only looks at the 
result if jcmd is used.

Long term solution may be to move functionality into native, but this is 
small and safe fix that can easily be backported.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8244508

Webrev:
http://cr.openjdk.java.net/~egahlin/8244508/

Testing: jdk/jdk/jfr

Thanks
Erik