Do not load program form file at every test (in cairo_run)

[Timothée Delabrouille]

IO is expensive.
Each test file can contain multiple tests.
Right now we re-read the compiled file before running each test in cairo.rs:

let program = match Program::new(path, entrypoint)

What we can do instead is use cairo-rs deserialize_program_json once. And then use build our Program directly from this in-memory json + the entrypoint

What to do:

• change cairo-rs deserialize_program implem by factorizing the second part of the function in another public method
• call deserialize_program_json once then pass it to this new function each time we want to run new

[Nathan GD]

I will take care of this issue :)