Add script diff two runs.
Add script diff two runs.

It's useful to see what output has changed. This mostly filters out
stuff we expect to change to reduce the noise.

alex-slynko/tile-generator,alex-slynko/tile-generator,cf-platform-eng/tile-generator,alex-slynko/tile-generator,cf-platform-eng/tile-generator,cf-platform-eng/tile-generator,cf-platform-eng/tile-generator,alex-slynko/tile-generator