Adds the ability for the GraphAssembler to operate on, and maintain, a
scheduled graph. This will be used by TurboProp to maintain the initial
schedule created before effect-control-linearization, by updating this schedule
during effect-control, select and memory lowering stages rather than doing a
later reschedule.

In order to do this, an internal BlockUpdater is added to GraphAssembler,
which is enabled by passing the schedule to the GraphAssembler. The
GraphAssembler is modified to call into the block updater when nodes are added
and updates the schedule with new basic blocks when new control flow is updated.

BUG=v8:9684

Change-Id: I6d428ad21d869c472bb20f43cc8caf44722f090a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1841355
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64519}