test: Add tests for canonisation with unreachable states

test/checker/reg/mic-unreach.0.ok

+init=1 (1,a)=2 (1,b)=3 (2,a)=2 (2,b)=2 (3,a)=3 (3,b)=3 final={2}

test/checker/reg/mic-unreach.1.nok

+init=1 (1,a)=3 (1,b)=2 (3,a)=2 (2,b)=2 (3,a)=3 (3,b)=3 final={3}

test/checker/reg/mic-unreach.2.nok

+init=1 (1,a)=2 (1,b)=3 (2,a)=2 (2,b)=2 (3,a)=3 (3,b)=3 (4,a)=4 (4,b)=4 final={2}

test/checker/reg/mic-unreach.q

+DFA-MIC:init=A (A,a)=B (A,b)=C (B,a)=B (B,b)=B (C,a)=C (C,b)=C final={B}