gh-71587: Establish global state in `_datetime` (#110475) #311

Job	Run time
Check for source changes	11s
Windows (x64)	22m 34s
Windows (x86)	17m 37s
Check if generated files are up to date	3m 50s
macOS	20m 28s
Windows (arm64)	5m 28s
Ubuntu	13m 39s
Docs	0s
Address sanitizer	14m 29s
Ubuntu SSL tests with OpenSSL (1.1.1w)	3m 52s
Ubuntu SSL tests with OpenSSL (3.0.11)	3m 25s
Ubuntu SSL tests with OpenSSL (3.1.3)	3m 35s
CIFuzz	0s
Hypothesis tests on Ubuntu	6m 51s
All required checks pass	3s
	1h 56m 2s

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