Early stopping when false=true

[eytans]

We should add a mechanism to detect bad "colors". We can say a color is bad if it has proven something that can not be. Colors are implemented under the assumption that only a few colored unions will happen, but when we add a false assumption it can imply that false = true, and the entire E-Graph can fold into a single E-Class which will be very expensive.

• Detect vacuity using classes_by_op
• Create delete_color
• Implement automatic runner hooks to delete colors
  • Make this optional for experiments
• Collect to stats how many colors were deleted