This uses the aforementioned helper within the {FastAccessorAssembler}.
It was made available as a helper function now that several users create
code objects following {kCallJSFunction} linkage via the {CodeAssembler}.

R=vogelheim@chromium.org

Review-Url: https://codereview.chromium.org/2644033003
Cr-Commit-Position: refs/heads/master@{#42516}