This CL generalizes and improves how we handle allocations in Torque.

Overview of the changes:
- Remove obsolete special handling for JSObject classes, since it was
  incomplete: It breaks as soon as slack tracking is active.
- Handle array initialization using slices.
- Properly align allocation sizes. This enabled allocating strings.
- Port AllocateSeq{One,Two}ByteString to Torque, which is much easier
  now than the old CSA code since allocation size alignment and
  large-object space allocation just happen out-of-the-box.
- Remove obsolete or unnecessary intrinsics, some of them turn into
  macros in the torque_internal namespace.
- Distinguish between header size and overall size for ClassType,
  make size optional and only defined when it is statically known.


Bug: v8:10004 v8:7793
Change-Id: I623db233e7fb4deed54e8039ae0c24705e9a44e8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1932356Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65397}