Easy way to determine which graph passes get applied

[TobyRoseman]

We have a large number of graph pass optimizations. When a model gets optimized, it's not clear which passes actually get applied (i.e. change the MIL graph). We should have an easy way to determine this.

Determining this information might be computationally costly; there may be no better way to determine it than comparing the graph before and after each pass runs. We probably don't want this behavior enabled by default.