When Promise.all is called with something which violates the iterable
contract, the resulting error should be provided by returning a rejected
promise, not by throwing.

Bug: v8:7553
Change-Id: I2769b09b49c9b80ef380419489416fc0fabff51b
Reviewed-on: https://chromium-review.googlesource.com/959599
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51902}