The doubleDoubleSum VM built-in function uses a special summation algorithm which works better when summing up a series (> 2) of integral values. It should also allow to preserve the existing semantics for this specific scenario.

We should still use the generic addition instruction for ExpressionAdd with two operands. Also, the existing translation logic for ExpressionAdd assumes it can only be called with two operands, which is not the case and needs to be fixed.