What's up with python3.12.abi.new having 22,644 additions?

Wow, that's some error. Let me clean that up

Ugh, force-push. :-(

I was going to ask "doesn't this break things for encodings where NULLs are normal, like UTF-16", but then realized we never supported that anyway:

PEP 253: "It does not include encodings which use two or more bytes for all characters like e.g. UTF-16. The reason for this is to keep the encoding detection algorithm in the tokenizer simple."

In that sense, we get a better error message for UTF-16 files with this PR than before. Prior, it would silently fail (behave as if an empty file), and with this PR:

  File "x.py", line 1
    #
SyntaxError: source code cannot contain null bytes

Landing, thank you everyone for your great review and comments! And also thank @mdboom for checking the UTF-16, that was a good consideration :)

P.S. Sorry for the force push :S