This is a reland of 8ff8ddba

Original change's description:
> [turbofan] Further brokerize BytecodeGraphBuilder
> 
> Replace all usages of VectorSlotPair with FeedbackSource.
> 
> Bug: v8:7790
> Change-Id: I0ac6e9cd8f5730154cc1842e267ca1ebfdebc874
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1763536
> Commit-Queue: Maya Lekova <mslekova@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63378}

Bug: v8:7790
Change-Id: I54fbf4433a65681780fda4ded09ec2d145d36ec1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1768361Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63391}