Backported RNG_MT19937 from master.

modules/core/test/test_rand.cpp

@@ -339,3 +339,29 @@ protected:
 
 TEST(Core_Rand, range) { Core_RandRangeTest test; test.safe_run(); }
 
+
+TEST(Core_RNG_MT19937, regression)
+{
+    cv::RNG_MT19937 rng;
+    int actual[61] = {0, };
+    const size_t length = (sizeof(actual) / sizeof(actual[0]));
+    for (int i = 0; i < 10000; ++i )
+    {
+        actual[(unsigned)(rng.next() ^ i) % length]++;
+    }
+
+    int expected[length] = {
+        177, 158, 180, 177,  160, 179, 143, 162,
+        177, 144, 170, 174,  165, 168, 168, 156,
+        177, 157, 159, 169,  177, 182, 166, 154,
+        144, 180, 168, 152,  170, 187, 160, 145,
+        139, 164, 157, 179,  148, 183, 159, 160,
+        196, 184, 149, 142,  162, 148, 163, 152,
+        168, 173, 160, 181,  172, 181, 155, 153,
+        158, 171, 138, 150,  150 };
+
+    for (size_t i = 0; i < length; ++i)
+    {
+        ASSERT_EQ(expected[i], actual[i]);
+    }
+}