Avoid dynamic initial map check when inlining call-new.

This improves check elimination and removes a load plus
a map check for every inlined call-new.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/293223002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21458 ce2b1a6d-e550-0410-aec6-3dcde31c8c00