sim: h8300: fix test mach markers

These tests all fail to assemble when targeting the h8300 or h8300h
cpu variants with errors like:
rotl.s:242: Warning: Opcode `rotl.b' with these operand types not available in H8/300H mode
rotl.s:242: Error: invalid operands

It's been this way for years and no one seems to care, so disable
them for those targets since the assembler thinks it's impossible.