In this simple example, you don't need simulations. Analytically, the expected growth rate for a large number of trials of the rebalancing case is 0.5*ln(1+0.5)+0.5*ln(1-0.25) = 0.059. That is, 5.9% expected growth each period. For the full investment case, 0.5*ln(1+1.0)+0.5*ln(1-0.5) = 0.