Allows JS functions returning array-like objects to be imported as
multi-return functions in WebAssembly modules. Importing a generator
does not work as required by the specification yet.

R=mstarzinger@chromium.org

Bug: v8:9492
Change-Id: Iaf61a0f718eb50676913aa1486fb39cebecfc090
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1815246
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63965}