SlithIR: Incorrect conversion of return tuple

[montyly]

Slither does not convert correctly return with tuple expression:

contract Test{

    function test(uint a, uint b) returns(uint, uint){
        return(a,b);
    }   

    function test2(uint a) returns(uint){
        return(a);
    }   

    function test3(uint a) returns(uint){
        return a;
    }
}

Only test3 is correctly translated to slithir:

	Function test(uint256,uint256)
		Expression: (a,b)
		IRs:
	Function test2(uint256)
		Expression: (a)
		IRs:
	Function test3(uint256)
		Expression: a
		IRs:
			RETURN a