chain of 200,000 adds: 400,001 nodes; build 4.09s, toposort 0.62s, evaluate 0.64s, simplify 14.19s
evaluate gives -1,474,736,480, the sum 1..200,000 is 20,000,100,000 wrapped to int32: -1,474,736,480
simplify merged all 200,000 constants into one: the result has 3 nodes, an ADD of x and the constant -1,474,736,480
