This relands squashed CLs:

59b9aaf7
8f84d0bb

The revert was at crrev.com/c/2996198.

Changed: Fixed a test in which bytecode flushing caused a behavioral
change between serialized- and unserialized SFI Refs. The serialized
SFI ref kept bytecode alive while unserialized SFIs allow flushing.
The test was fixed by adding a %PrepareFunctionForOptimization
annotation.

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7790, v8:11939
Change-Id: I170f8085bd7454a2a5f2bb03c8824e2862857827
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2999089
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75504}