RFR: 8138972: G1CollectorPolicy::_max_survivor_regions should be intialized in the initializer list

[Erik Helin]

Hi all,

this tiny patch removes a comment that is no longer true and changes
G1CollectorPolicy::_max_survivor_regions to be initialized in the
initializer list of the G1CollectorPolicy constructor.

Enhancement:
https://bugs.openjdk.java.net/browse/JDK-8138972

Webrev:
http://cr.openjdk.java.net/~ehelin/8138972/webrev.00/

Testing:
JPRT

Thanks,
Erik