Tests

Increase the number of items for ooc merge sorts #3367

Job	Run time
Build and test on ubuntu-latest (python 3.12)	10m 44s
Build and test on windows-latest (python 3.12)	19m 16s
Build and test on macos-latest (python 3.12)	13m 49s
Build and test on ubuntu-latest (numpy 1.26)	11m 48s
Build and test on ubuntu-latest (python 3.14)	11m 57s
	1h 7m 34s

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