[#319] Handle exception case of euclidean division in Michelson style

Description

Euclidean division operation divMich a b performs division of a and b incorrectly when mod a b == 0. It was described in one MR that integer division performances differ in Michelson and in Haskell. So when divisor is negative and divisible number is multiple of divisor, the results are equal in Michelson and in Haskell.

As a solution we need to handle this case in divMich and don't change the result of div if mod a b == 0.

Related issue(s)

Resolves #319 (closed)

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