Remove unused import from tests #339

Job	Run time
rust-test (ubuntu-latest)	50s
rust-test (macos-latest)	58s
rust-test (windows-latest)	1m 54s
no_std and miri (ubuntu-latest)	3m 51s
python-test (3.7, ubuntu-latest)	33s
no_std and miri (macos-latest)	5m 46s
python-test (3.7, macos-latest)	1m 46s
no_std and miri (windows-latest)	5m 3s
python-test (3.7, windows-latest)	2m 32s
python-test (3.8, ubuntu-latest)	46s
python-test (3.8, macos-latest)	1m 54s
python-test (3.8, windows-latest)	1m 46s
python-test (3.9, ubuntu-latest)	1m 0s
python-test (3.9, macos-latest)	1m 6s
python-test (3.9, windows-latest)	1m 51s
python-test (3.10, ubuntu-latest)	52s
python-test (3.10, macos-latest)	54s
python-test (3.10, windows-latest)	2m 18s
python-test (3.11, ubuntu-latest)	35s
python-test (3.11, macos-latest)	1m 0s
python-test (3.11, windows-latest)	1m 49s
python-test (3.12, ubuntu-latest)	50s
python-test (3.12, macos-latest)	1m 8s
python-test (3.12, windows-latest)	2m 24s
Meta job for all tests	1s
	43m 27s

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