This changes the BytecodeGraphBuilder to connect runtime calls that
don't return normally, but always throw exceptions, to End (via a Throw
node), instead of inserting Phis on the return values. This unblocks
the new optimization approach for array iteration.

Bug: v8:7510, v8:7514
Change-Id: Ic78216cc27034f191c4850e476f24e598c17deca
Reviewed-on: https://chromium-review.googlesource.com/946250Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51702}