Add tests for new 2024.12 functionality

[asmeurer]

This is a tracking issue for testing new 2024.12 functionality.

There isn't a changelog yet, but the new functionality that I'm aware of is:

New functions

• diff (test diff #369)
• nextafter (ENH: test nextafter #366)
• reciprocal
• take_along_axis (ENH: test take_along_axis #367)
• count_nonzero
• cumulative_prod

New Functionality

• The 'max dimensions' key of __array_namespace_info__().capabilities() (note that capabilities itself is not yet tested at all, see 2023.12 support #249) -- some smoke-testing in ENH: some more tests of inspection functions #362

Scalar support: most functions are (lightly) tested. After gh-348, the following binary functions are still not tested at all:

• bitwise_right_shift (test pow() and bitwise shifts with scalars #371)
• bitwise_left_shift (test pow() and bitwise shifts with scalars #371)
• nextafter (ENH: test nextafter #366)
• where (ENH: test where with scalars #370)
• pow (test pow() and bitwise shifts with scalars #371)
• result_type ( ENH: improve testing of result_type #349 )

[ev-br]

cross-ref #324 for testing reciprocal and cumulative_prod.

[ev-br]

#347 adds a test for count_nonzero

[ev-br]

We now officially have the 2024.12 test coverage. At least all new functions are covered, with remaining TODOs tracked in gh-301 and gh-364.