Since Crankshaft specializes to the native context anyways, we don't
need the indirection of loading from the native context and calling the
JS runtime function indirectly, but we can just specialize to the JS
runtime function from the native context and emit a direct (constant)
function call.

BUG=chromium:592692,chromium:595265
R=ishell@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/1807003002

Cr-Commit-Position: refs/heads/master@{#34842}