This is a reland of d7ece57e with
a fix to failures on NumFuzz.

Original change's description:
> [turboprop] Add a slot for optimization marker in feedback vector
>
> Optimization marker and the optimized code used to share the same slot
> in the feedback vector as they were mutually exclusive. With turboprop
> we would want to mark the function for tier up to Turbofan while holding
> the optimized code for Turboprop. So this cl uses the existing padding
> field to hold the optimization marker instead.
>
> As a driveby, removes unused JSFunction::ClearOptimizedCodeSlot function
> and fixes a minor bug in Runtime_GetOptimizationStatus.
>
> Bug: v8:9684
> Change-Id: I18c551a69648a0837d16c5453d023c0b295b1521
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2467836
> Commit-Queue: Mythri Alle <mythria@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70789}

Bug: v8:9684
Change-Id: Ie6aa3c061a852bb047b5921e4e747d43505568e3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2502871
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70834}