This patch provides infrastructure to pin object types to specific
spaces. This allows embedders to create mutual exclusive arenas for
certain (base) types. In future, this will also be used to provide
sliding-window compaction on certain custom spaces.

We mainly preserve the existing infrastructure with the difference
that spaces are now slightly more dynamic than in Blink as they are
kept in a vector instead of a fixed-size array.

The mechanism differs from Blink in that it does not allow the user
object to call allocation methods directly but instead provides a
trait that can be overridden to specify a custom space.

The patch preserves templatization for objects that do not go into
custom spaces to safe a branch in the allocation hot path.

Change-Id: I08aa6932348e2d6258e19c4a32d189865f459f02
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2187611
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67666}