The Intl implementation included manual checks to see if they were
being called as a constructor. However, these checks are redundant,
as %FunctionRemovePrototype has already marked the functions as
un-constructable. This path removes the unnecessary checks.
R=yangguo
Review-Url: https://codereview.chromium.org/2587713002
Cr-Commit-Position: refs/heads/master@{#41867}
