gh-114315: Make `threading.Lock` a real class, not a factory function (#114479)

`threading.Lock` is now the underlying class and is constructable rather than the old
factory function. This allows for type annotations to refer to it which had no non-ugly
way to be expressed prior to this.

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Co-authored-by: Alex Waygood <[email protected]>
Co-authored-by: Gregory P. Smith <[email protected]>