RFR: 8203929: Limit amount of data for JFR.dump

[Erik Gahlin]

Hi,

Could I have a a review of an enhancement that will simplify the usage 
of JFR.dump and make it possible to copy parts of a recording to a 
file.  For more information, see the CSR:

https://bugs.openjdk.java.net/browse/JDK-8203930

Bug:
https://bugs.openjdk.java.net/browse/JDK-8203929

Webrev:
http://cr.openjdk.java.net/~egahlin/8203929/

Testing:
Tests in test/jdk/jdk/jfr

Thanks
Erik