message: core: vectorize countNonZero64f
  Improves performance a bit. 2.2x on P9 and 2 - 3x on coffee lake
  x86-64.
diff: @@ -179,7 +179,25 @@ static int countNonZero32f( const float* src, int len )
  static int countNonZero64f( const double* src, int len )
  {
  - return countNonZero_(src, len);
  + int nz = 0, i = 0;
  +#if CV_SIMD_64F
  + v_int64 sum1 = vx_setzero_s64();
  + v_int64 sum2 = vx_setzero_s64();
  + v_float64 zero = vx_setzero_f64();
  + int step = v_float64::nlanes * 2;
  + int len0 = len & -step;
  +
  + for(i = 0; i < len0; i += step )
  + {
  + sum1 += v_reinterpret_as_s64(vx_load(&src[i]) == zero);
  + sum2 += v_reinterpret_as_s64(vx_load(&src[i + step / 2]) == zero);
  + }
  +
  + // N.B the value is incremented by -1 (0xF...F) for each value
  + nz = i + (int)v_reduce_sum(sum1 + sum2);
  + v_cleanup();
  +#endif
  + return nz + countNonZero_(src + i, len - i);
  }
  CountNonZeroFunc getCountNonZeroTab(int depth)
  