OP's tire is gone bad and he needs a new one. At least, I'd say. But who cares what I think?

No other motor vehicle tire manufacturers or tire shops will tell you that it's safe to use cracked tires.
And probably, no bicycle tire companies either.

If you want to try to save a buck and you think that bicycles are magically different somehow than everything else with pneumatic tires, go right ahead and keep on using it--but a new tire is going to look pretty cheap if you crash because of this and need any kind of medical care.