Add support to flush only baseline code. FLAG_flush_baseline_code
controls if baseline code is flushed or not and FLAG_flush_bytecode
controls if bytecode is flushed or not. With this CL it is possible
to control if we want to flush only bytecode / only baseline code / both.
This also lets us have different heuristics for bytecode and baseline
code flushing.

Bug: v8:11947
Change-Id: Ibdfb9d8be7e7d54196db7890541fa0b5d84f037e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3060481Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76075}