This is a reland of f4548e75

Original change's description:
> [regalloc] Place spill instructions optimally
>
> Design doc:
> https://docs.google.com/document/d/1n9ADWnDI-sw0OvdSmrthf61prmDqbDmQq-NSrQw2MVI/edit?usp=sharing
>
> Most of this change follows directly what is discussed in the design
> document. A few other things are also changed:
>
> - PopulateReferenceMapsPhase is moved after ResolveControlFlowPhase so
>   that it can make use of the decision regarding whether a value is
>   spilled at its definition or later.
> - SpillSlotLocator is removed. It was already somewhat confusing,
>   because the responsibility for marking blocks as needing frames was
>   split: in some cases they were marked by SpillSlotLocator, and in
>   other cases they were marked by CommitSpillsInDeferredBlocks. With
>   this change, that split responsibility would become yet more
>   confusing if we kept SpillSlotLocator for the values that are spilled
>   at their definition, so I propose a simpler rule that whatever code
>   adds the spill move also marks the block.
> - A few class definitions (LiveRangeBound, FindResult,
>   LiveRangeBoundArray, and LiveRangeFinder) are moved without
>   modification from register-allocator.cc to register-allocator.h so
>   that we can refer to them from another cc file.
>
> Bug: v8:10606
> Change-Id: I374a3219a5de477a53bc48117e230287eae89e72
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2285390
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69345}

Bug: v8:10606
Change-Id: I10fc1ef4b0bebb6c9f55ebdefe33e8c1e5646f0a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2352483
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69427}