When rewiring a block to throw, we need to remove the current block from the list
of predecessors for all of our successors, as well as clearing our current successors.

BUG=v8:9684

Change-Id: I0da063b2ef707f07ea27a5f72cabd2ff9a91cc42
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1881154Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64579}