This is a preliminary step for adding support for additional flags and return types.

Bug: v8:7754, v8:6600
Change-Id: I1f65ec41f22b61a9471eb7105033007744563e91
Reviewed-on: https://chromium-review.googlesource.com/1107917
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53894}