Make checker handle not executing the same instruction as the main CPU a little better.

Make checker handle not executing the same instruction as the main CPU a little better.
Also add the option for the checker to update itself with the main CPU's state if it executes an instruction differently (so it will handle DMA timing errors properly).

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extra : convert_revision : 760d11ec1a249bc75e2807d320866b5d08c2b6f2