Enable physical memory argument to be passed as an argument to ConfigureResourceConstraintsForPlatform.

BUG=312241
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/68203003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17696 ce2b1a6d-e550-0410-aec6-3dcde31c8c00