[M68k] Add support for bitwise NOT instruction (#88049)

Currently the bitwise NOT instruction is not recognized. Add support for
using NOT on data registers. This is a partial implementation that puts
NOT at the same level of support as NEG currently enjoys.

Using not rather than eori cuts the length of the encoded instruction
in half or in thirds, leading to a reduction of 4-10 cycles per
instruction, on the original 68000.

This change includes tests for both bitwise and arithmetic negation.