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
• nextafter
• reciprocal
• take_along_axis
• 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)

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

• bitwise_right_shift
• bitwise_left_shift
• nextafter
• where
• pow
• 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