RFR: 8033426: Scale initial NewSize using NewRatio if not set on command line

[Stefan Johansson]

Hi,

Can I have a couple of reviews for this enhancement:
https://bugs.openjdk.java.net/browse/JDK-8033426

Webrev:
http://cr.openjdk.java.net/~sjohanss/8033426/webrev.00/

Summary:
Currently the initial young generation size is the same as the minimum. 
If not using large pages this will be 1.5M for the default collector 
regardless of how large the whole heap is. The proposed change is to 
scale the initial young size the same way the maximum young size is 
scaled, using the NewRatio parameter.

Note:
This change has been out on review as part of the fix for JDK-8028498, 
but after discussions we have decided take another approach for that bug.

Testing:
* JPRT
* GC tests in jtreg

Thanks,
Stefan