Object.create is most often called with a single parameter, the
prototype, and the properties are usually omitted. So optimizing
for the common case, we remove the argument adaption.

R=jgruber@chromium.org
BUG=v8:5989

Review-Url: https://codereview.chromium.org/2953913002
Cr-Commit-Position: refs/heads/master@{#46153}