Added perf test for distanceTransform

modules/imgproc/perf/perf_distanceTransform.cpp

+#include "perf_precomp.hpp"
+#include "distransform.cpp"
+
+using namespace std;
+using namespace cv;
+using namespace perf;
+
+typedef perf::TestBaseWithParam<Size> Size_DistanceTransform;
+
+PERF_TEST_P(Size_DistanceTransform, icvTrueDistTrans, testing::Values(TYPICAL_MAT_SIZES))
+{
+    Size size = GetParam();
+    Mat src(size, CV_8UC1);
+    Mat dst(size, CV_32FC1);
+    CvMat srcStub = src;
+    CvMat dstStub = dst;
+
+    declare.in(src, WARMUP_RNG).out(dst);
+
+    TEST_CYCLE() icvTrueDistTrans(&srcStub, &dstStub);
+
+    SANITY_CHECK(dst, 1);
+}