Reland "[partition_alloc] Add alternate bucket distribution for PartitionAlloc"

This is a reland of bb317f4d

Original change's description:
> [partition_alloc] Add alternate bucket distribution for PartitionAlloc
>
> This should not change any behaviour, but merely allow us to run a Finch
> experiment comparing the two distribution.
>
> Bug: None
> Change-Id: Ifaac5a1cbcf5d21ce44fa626f57b91a3ed4d7a69
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3272015


> Reviewed-by: Benoit Lize <lizeb@chromium.org>
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Commit-Queue: Thiabaud Engelbrecht <thiabaud@google.com>
> Cr-Commit-Position: refs/heads/main@{#965816}

Bug: None
Change-Id: I111e1a0dca8049e9c8d412fd0f5ca5eb8fa9104c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3442629


Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Benoit Lize <lizeb@chromium.org>
Commit-Queue: Thiabaud Engelbrecht <thiabaud@google.com>
Cr-Commit-Position: refs/heads/main@{#968373}