Test Case 5:

Cells between two hot and cold bouindaries are initialized with temperature value -3000 degrees.
The solution converges to correct answer with same precision of last test (test case 4)
after 33 steps compared to same precision after 17 steps in ( test case 4) as shown on output file.
This shows that the simulation converges faster to the solution if initialized with reasonably
predicted values. This can cut simulation time when simulating small disturbances in the
boundary conditions applied to model boundaries.