This CL exposes IteratorBuiltinsAssembler::IterableToList as a builtin
to reduce generated code duplication. This follows up on CL 1201882.

Change-Id: I848e17bd1b6756de9e898e9d2f8c93d99699df07
Reviewed-on: https://chromium-review.googlesource.com/1206470
Commit-Queue: Hai Dang <dhai@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55641}