This merges all control edges that are known to unconditionally throw
directly into the graph end node. This applies to the "Throw" as well as
the "Rethrow" operation, and reduces their code size.

R=clemensh@chromium.org
BUG=v8:8091

Change-Id: Idd4918ab084bcc697d5798d512ccc695ca943b00
Reviewed-on: https://chromium-review.googlesource.com/c/1305273Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57119}