Since we only care about execution order for the purposes of seeing whether we
have truly seen all of a match block, check for that specifically rather than
trying to come up with some more general heuristics for detecting any
out-of-order opcodes.

PiperOrigin-RevId: 605197589

PiperOrigin-RevId: 605387768

PiperOrigin-RevId: 605392927

* Adds basic function call support. The current frame creates a new frame, sets
  the new frame's 'f_back' attribute to itself, and runs the new frame.
* Copies over globals when creating a new frame, and merges any changed globals
  back into f_back when a frame finishes running.
* Adds a bit more structure to analyze.py and vm.py to lay the groundwork for
  analyzing functions and classes once the module-level code has run.
* Moves the data stack to its own module.
* Renames globals to initial_globals to reflect that it isn't updated as a
  frame modifies globals.
* Adds a with_name() convenience method to Variable.

PiperOrigin-RevId: 605407504

PiperOrigin-RevId: 605682622