narrow_i32x4_s: Wasm SIMD conversion instruction

(module
  (import "console" "log" (func $log (param i32)))
  (func $main
    v128.const i32x4 200 210 220 230
    v128.const i32x4 300 310 320 330

    i16x8.narrow_i32x4_s
    i16x8.extract_lane_s 7
    call $log ;; log the result
  )
  (start $main)
)

WebAssembly.instantiateStreaming(fetch("{%wasm-url%}"), { console });