Context

bindings/python/test/test_mongocrypt.py keeps the sync and async suites in one file, written by hand. They have already drifted: test_rangePreview_query_int32 exists only in the sync suite, so nothing asserts that the deprecated rangePreview algorithm raises on the async path. We should use something similar to pymongo's synchro script to keep the test files in sync.

Definition of done

• The async suite covers the deprecated rangePreview algorithm.
• The sync test files under bindings/python/test/ are generated, not hand-mirrored.
• A pre-commit hook fails when they are out of date, as synchro does in pymongo.

Pitfalls

• unasync transforms files between two directories, so the single test file needs splitting first. That is the bulk of the work.