Add a version number to code objects

[markshannon]

We want to add a version number to code objects, so that all functions that are created from the same code object have the same version number (at least until they are mutated).

Code objects are immutable, so they do not need a version number themselves, it is just to help function objects.
By ensuring that all function objects created from the same code object have the same version number, we can effectively specialize comprehensions and inner functions.

See faster-cpython/ideas#446 for more details.

• PR: GH-98522: Add version number to code objects, to provide better version numbers for closures and comprehensions. #98525