Replace direct call to generated code with call using GeneratedCode to
match the rest of v8.

BUG=v8:7164

Change-Id: I3e45d3e7c45f06fc362a22217ee7f0f1b70745e2
Reviewed-on: https://chromium-review.googlesource.com/1002534
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52536}