Add support to verify the update schedule after ScheduledEffectControlLinearization
and ScheduledMachineLowering phases. To do so, we need to recompute the immediate
dominator tree of the scheduled blocks.

BUG=v8:9684

Change-Id: I849fb7e3e699ca56c5115d90a53006d517cf3fe5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1881160
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64596}