This CL adds a new FreeList strategy, that can be turned on by using
flag `--gc-freelist-strategy=2`. It uses a lot (about 50)
FreeListCategories instead of the 6 ones used in FreeListLegacy.
Allocation is done using a best-fit strategy. However, FreeListMany
could be subclassed in order to change the allocation strategy while
still using the same freelists.

Using this strategy is expected to reduce memory usage but to also
reduce allocation performances.

Bug: v8:9329
Change-Id: I201be863270a3287701fefdd9e14ba7849a8a551
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1698392
Commit-Queue: Darius Mercadier <dmercadier@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62731}