Increase the target new space size to the max new space size

Increase the target new space size to the max new space size

Assuming a page creates a low of objects that however will soon die
after page load, delaying the first scavange will hopefully decrease the
amount of time spent during page load without a later penalty when we
have to scavenge a large but mostly dead new space

BUG=v8:3626
R=hpayer@chromium.org
LOG=y

Committed: https://code.google.com/p/v8/source/detail?r=25298

[jochen (gone - plz use gerrit), 2014-11-12 08:34:13]

ptal

[Hannes Payer (out of office), 2014-11-12 12:15:40]

lgtm

[jochen (gone - plz use gerrit), 2014-11-12 14:46:29]

Committed patchset #1 (id:1) manually as 25298 (presubmit successful).