IncrementalDAGBuilder fails for traces with cyclic repetitions longer than 2

[mtf90]

Describe the bug Inserting certain traces into an Incremental(Mealy)DAGBuilder throws a ConflictException.

To Reproduce

import net.automatalib.alphabet.Alphabet;
import net.automatalib.alphabet.impl.Alphabets;
import net.automatalib.incremental.mealy.dag.IncrementalMealyDAGBuilder;
import net.automatalib.word.Word;

public class IncrementalMealyDAGError {

    public static void main(String[] args) {

        final Alphabet<Character> alphabet = Alphabets.characters('0', '3');

        final Word<Character> in1 = Word.fromString("12");
        final Word<Character> in2 = Word.fromString("302");
        final Word<Character> in3 = Word.fromString("3023102");
        final Word<Character> in4 = Word.fromString("30231023");

        final Word<Character> out1 = Word.fromString("21");
        final Word<Character> out2 = Word.fromString("101");
        final Word<Character> out3 = Word.fromString("1013201");
        final Word<Character> out4 = Word.fromString("10132010");

        final IncrementalMealyDAGBuilder<Character, Character> builder = new IncrementalMealyDAGBuilder<>(alphabet);

        builder.insert(in1, out1);
        builder.insert(in2, out2);
        builder.insert(in3, out3);
        builder.insert(in4, out4); // boom
    }
}

Expected behavior No exception should be thrown.

Desktop (please complete the following information):

• OS: Linux
• Java version: 11/17/21
• AutomataLib version: 0.11.0

Additional context This issue was originally reported as LearnLib/learnlib#126.