Draw function is not reset when Restart is pressed

If you have a program that starts with no `draw` function defined, but later define one, then when you click Restart, the program will start with the draw function defined. I've made a simple demonstration:
https://www.khanacademy.org/computer-programming/spin-off-of-click-a-button-any-button/6142122579

The program starts without a `draw` function, just drawing some text. When you click it defines a `draw` function. If you press Restart, the program starts with the newly defined `draw` functions. This was confusing the creator of the code that I spun-off from into thinking the Restart button was broken.

Start with the linked demonstration and trace the Restart control's program reset path, focusing on how the runtime handles a draw function created after startup. Done means pressing Restart returns to the original no-draw state rather than retaining the dynamically defined function.

Written by the indexing model from the issue text.