Hosts without NEON or SSE2 ran vfpu_dot_reference() for every dot product. vfpu_dot_scalar() is
the same computation without its branches, finished like the SIMD versions, and is what RISC-V
gets. LoongArch builds with LSX (GCC's default la64v1.0 has it) get vfpu_dot_lsx(), the SSE2
version in LSX.
VFPUDot checks vfpu_dot_scalar() on every host, and its inputs come from ForEachVFPUDotTestCase(),
for the JITs' routines to use too.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
