Remove incorrect qrdmulh SSE code.

The only reason the SSE code for qrdmulh passed is because the edge
cases were not included in the tests unless SSE was disabled.  The
INT16_MIN * INT16_MIN case ought result in INT16_MAX - and it does,
in the fallback code.  It does not, in the SSE code, which is
what will typically be used on x86 hardware.  Saturating code not
handling edge cases is simply wrong.

arm/neon/qrdmulh.h

@@ -128,29 +128,8 @@ simde_vqrdmulhq_s16(simde_int16x8_t a, simde_int16x8_t b) {
       a_ = simde_int16x8_to_private(a),
       b_ = simde_int16x8_to_private(b);
 
-    /* https://github.com/WebAssembly/simd/pull/365 */
     #if defined(SIMDE_ARM_NEON_A32V7_NATIVE)
       r_.neon_i16 = vqrdmulhq_s16(a_.neon_i16, b_.neon_i16);
-    #elif defined(SIMDE_X86_SSSE3_NATIVE)
-      __m128i y = _mm_mulhrs_epi16(a_.m128i, b_.m128i);
-      __m128i tmp = _mm_cmpeq_epi16(y, _mm_set1_epi16(INT16_MAX));
-      r_.m128i = _mm_xor_si128(y, tmp);
-    #elif defined(SIMDE_X86_SSE2_NATIVE)
-      const __m128i prod_lo = _mm_mullo_epi16(a_.m128i, b_.m128i);
-      const __m128i prod_hi = _mm_mulhi_epi16(a_.m128i, b_.m128i);
-      const __m128i tmp =
-        _mm_add_epi16(
-          _mm_avg_epu16(
-            _mm_srli_epi16(prod_lo, 14),
-            _mm_setzero_si128()
-          ),
-          _mm_add_epi16(prod_hi, prod_hi)
-        );
-      r_.m128i =
-        _mm_xor_si128(
-          tmp,
-          _mm_cmpeq_epi16(_mm_set1_epi16(INT16_MAX), tmp)
-        );
     #else
       SIMDE_VECTORIZE
       for (size_t i = 0 ; i < (sizeof(r_.values) / sizeof(r_.values[0])) ; i++) {