tests: extend the SIMD kernel equivalence tests to NEON and SVE

[zirui-song-18]

Description

Extends the per-ISA kernel-equivalence tests (#39) to ARM. NEON links the base nsparse (the aarch64 baseline) and runs ungated; SVE links nsparse_sve, compiles with -march=armv8-a+sve, is built only off Apple, and is launch-gated on the sve CPU flag (a fully-+sve binary can execute SVE in a static initializer, so it must not start on a non-SVE CPU). NEON is exercised by CI's macOS (Apple Silicon) runner; SVE runs where the host advertises it (Graviton3).

Tested SVE on a r7g instance:

Start 607: nsparse_neon_kernel_test
607/608 Test #607: nsparse_neon_kernel_test ........................................................................................................   Passed    0.00 sec
        Start 608: nsparse_sve_kernel_test
608/608 Test #608: nsparse_sve_kernel_test .........................................................................................................   Passed    0.01 sec

100% tests passed, 0 tests failed out of 608

Total Test time (real) =   6.40 sec

Issues Resolved

List any issues this PR will resolve, e.g. Closes [...].

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