This allows the definition of classes with several arrays and ports
SmallOrderedHashTable subclasses to Torque as an example, including
the existing CSA allocation functions for them.

Overview of changes:
- Introduce ResidueClass to encapsulate the modulo-arithmetic
  necessary to do alignment checks.
- Add MachineOperatorReducer to the CSA pipeline to address now
  missing CSA ad-hoc constant folding that got blocked by a
  temporary phi.
- Allow assignments to references to structs. This is needed to
  initialize the data_table part of SmallOrderedHashMap.
- Make the NumberLiteralExpression AST-node store a double instead
  of a string. This is necessary to detect arrays with constant size
  used for padding.
- Turn offsets into base::Optional<size_t> to ensure we don't use
  an invalid or statically unknown offset.
- Remove CreateFieldReferenceInstruction since it doesn't work for
  complex offset computations and the logic can be expressed better
  in ImplementationVisitor.
- Validate alignment of structs embedded in classes.

Bug: v8:10004 v8:7793
Change-Id: Ifa414b42278e572a0c577bf9da3d37f80771a258
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1958011
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65538}