Use openblas in numpy recipe on 6x

[ianthomas23]

Template B: Checklist for updating a package

• ⚠️ Bump build number if the version remains unchanged
• Or reset build number to 0 if updating the package to a newer version

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PR Formatting

• PR title follows format: Add [package-name] or Update [package-name] to [version]
• PR description includes:
  • Version being added/updated
  • Any special build considerations or patches applied

Package Details

• Package Name: NumPy
• Version: 2.5.3 2.5.4

Build Notes

Rebuild of numpy on emscripten-6x to use openblas and to add separate numpy-tests package to run (almost) full test suite. This brings it into line with the existing recipe on main which includes significant PRs #6310 and #6676 thanks to @jjerphan.

Summary of changes compared to main:

1. Using repository's MESON_CROSS_FILE.
2. Patches rewritten to use correct-sized integers on both wasm32 and wasm64.
3. Some more tests are disabled on wasm64 for allocation of very large arrays.
4. New patch 0004 to correct integer size substituted in error message. This may be a real NumPy error, I will need to investigate further.
5. NumPy tests run with -p no:faulthandler, the same as openblas/scipy tests.

This builds and passes tests for me locally on wasm32 and wasm64.

Assuming this passes CI, there are two options for how to proceed:

1. Merge as is, so all use of numpy on emscripten-6x will use openblas.
2. Wait until the next numpy release (2.5.4) before updating and merging this. Then numpy >= 2.5.4 on emscripten-6x will use openblas but we will still have numpy 2.5.3 that does not use openblas in case we need this option in the future.