Add sanity checkes to video module perf tests

modules/video/perf/perf_optflowpyrlk.cpp

@@ -91,6 +91,10 @@ PERF_TEST_P(Path_Idx_Cn_NPoints_WSize, OpticalFlowPyrLK_full, testing::Combine(
                              Size(winSize, winSize), maxLevel, criteria,
                              flags, minEigThreshold);
     }
+
+    SANITY_CHECK(outPoints);
+    SANITY_CHECK(status);
+    SANITY_CHECK(err, 1e-5);
 }
 
 typedef tr1::tuple<std::string, int, int, tr1::tuple<int,int>, int, bool> Path_Idx_Cn_NPoints_WSize_Deriv_t;
@@ -166,6 +170,10 @@ PERF_TEST_P(Path_Idx_Cn_NPoints_WSize_Deriv, OpticalFlowPyrLK_self, testing::Com
                              Size(winSize, winSize), maxLevel, criteria,
                              flags, minEigThreshold);
     }
+
+    SANITY_CHECK(outPoints);
+    SANITY_CHECK(status);
+    SANITY_CHECK(err, 1e-5);
 }
 
 CV_ENUM(PyrBorderMode, BORDER_DEFAULT, BORDER_TRANSPARENT);