This is a reland of f5729f1c

TBR=ulan@chromium.org

Original change's description:
> [GC] Ensure JSFunctions with flushed bytecode are flushed during GC.
>
> When bytecode is flushed from a SFI, the JSFunctions still retain their
> FeedbackVector's and point to the interpreter entry trampoline. They are
> reset if re-executed, however if not they could hold onto the feedback
> vector indefinetly. This CL adds a pass the GC to detect JSFunctions that
> need to be reset, and performs the reset at the end of GC.
>
> BUG=v8:8395
>
> Change-Id: I3de8655aff9ff80f912b4fd51dee43eb98cfd519
> Reviewed-on: https://chromium-review.googlesource.com/c/1393292
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58775}

Bug: v8:8395
Change-Id: If9580b25ba32e4065e20d86cb8ed22a3280d59e9
Reviewed-on: https://chromium-review.googlesource.com/c/1424860Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59001}