CRR (XS): 7091032: G1: assert failure when NewRatio is used

[Tony Printezis]

Hi all,

I'd like to get a couple of code review for this very small change to 
avoid an assert failure when NewRatio is explicitly set 
(size_to_region_num() takes a size parameter in bytes, so passing a 
region number is incorrect):

http://cr.openjdk.java.net/~tonyp/7091032/webrev.0/

I also changed a tty->print_cr statement into a warning to be consistent 
with what we do in similar situations.

Thanks,

Tony