The SIMD cannot be disabled anymore. These are the 2 parts we need to fix:

• do not put -msimd128 to emcc-default.rsp, otherwise we compile with SIMD even when WasmEnableSIMD is false. Instead add it conditionally in src/mono/wasm/wasm.proj, src/mono/wasm/runtime/CMakeLists.txt and src/mono/wasm/build/WasmApp.Native.targets
• do not build our mono runtime with -msimd128 or provide multiple native libraries versions

optionally:

• do not pass '--enable-simd' to wasm-opt. I think this doesn't add any SIMD instructions, so we probably don't need it. We should check it though.

following step:

• add WBT test to check that build with SIMD disabled produces .wasm files without SIMD instructions. This can be done easily once we have the wa-info tool in the runtime repo.
• Run SIMD WBT with older Firefox (88) or Chrome to check it works on runtime
• Disable SIMD and WASM EH in Jiterpreter if it was disabled during build
• AOT complication produces some SIMD althought it was disabled