f32-spmm missing tests

[oliIMG]

Currently the way tests are generated and linked causes an issue where in the final binary 'f32-spmm-minmax-test' only the tests present in 'f32-spmm-minmax.cc' get included. I'm building for a RISC-V target but I don't believe target platform affects final output for the test binary.

I've managed to hack my way around this by generating the source code for the code in one file 'f32-spmm-minmax.cc' but this should get fixed properly. Also consider re-evaluating other tests that are split into multiple files.

[fbarchard]

SPMM was only implemented on ARM and WASMSIMD.
Unless there is a real usecase for it, I'd suggest making RISC-V follow what Intel did for this, disabling/skipping SPMM.

SPMM gives roughly 4:1 compression on floats, so 8 bit weights. But the current preferred approach is quantization of float weights to 8 or 4 bits. e.g. qd8_qc4w, which lends itself to more efficient byte dot product (sdot/vnni) or matrix instructions like Intel AMX (which is built upon dotproducts)

If you have a work around that can be done as a PR to disable SPMM on RISC-V that would be good