Arm: Add pass for replacing dq-q patterns with rescale (#8513)

When an int8 op meets an int32 op, the int8 is first
dequantized to a float which is then quantized to the
desired int8 dtype.

This produces a (int8 dq -> q int32) pattern that
we can replace with a TOSA.RESCALE since they are approximately
mathematically equivalent, differing only in how the rounding is done.

This requires a few changes:
- Introduce custom rescale op
- Create pass to replace the dq-q pattern with the rescale op
- Implement node_visitor for rescale op

The change makes it possible to mix int8 and int32 quantization,
as showcased in the new test_add_i32_tosa_BI test.

Signed-off-by: Erik Lundell <erik.lundell@arm.com>