message: imgproc(test): fix resize bitexact test
  use "random" area on input image
  avoid duplicate cases
diff: @@ -45,9 +45,9 @@ TEST(Resize_Bitexact, Linear8U)
  { CV_8UC4, Size( 4, 3) },
  { CV_8UC1, Size( 342, 384) }, // 1/3 1/2
  { CV_8UC1, Size( 342, 256) }, // 1/3 1/3
  - { CV_8UC1, Size( 342, 256) },
  - { CV_8UC1, Size( 342, 256) },
  - { CV_8UC1, Size( 342, 256) },
  + { CV_8UC2, Size( 342, 256) },
  + { CV_8UC3, Size( 342, 256) },
  + { CV_8UC4, Size( 342, 256) },
  { CV_8UC1, Size( 512, 256) }, // 1/2 1/3
  { CV_8UC1, Size( 146, 110) }, // 1/7 1/7
  { CV_8UC3, Size( 146, 110) },
  @@ -83,13 +83,13 @@ TEST(Resize_Bitexact, Linear8U)
  softdouble scale_y = softdouble::one() / softdouble(inv_scale_y);
  Mat src(rows, cols, type), refdst(drows, dcols, type), dst;
  + RNG rnd(0x123456789abcdefULL);
  for (int j = 0; j < rows; j++)
  {
  uint8_t* line = src.ptr(j);
  for (int i = 0; i < cols; i++)
  for (int c = 0; c < cn; c++)
  {
  - RNG rnd(0x123456789abcdefULL);
  double val = j < rows / 2 ? ( i < cols / 2 ? ((sin((i + 1)*CV_PI / 256.)*sin((j + 1)*CV_PI / 256.)*sin((cn + 4)*CV_PI / 8.) + 1.)*128.) :
  (((i / 128 + j / 128) % 2) * 250 + (j / 128) % 2) ) :
  ( i < cols / 2 ? ((i / 128) * (85 - j / 256 * 40) * ((j / 128) % 2) + (7 - i / 128) * (85 - j / 256 * 40) * ((j / 128 + 1) % 2)) :
  