imgproc(perf): update getPerspectiveTransform perf test
imgproc(perf): update getPerspectiveTransform perf test

Function is very fast, so 0.000 ms results are useless.
1000 runs requires 25ms on i7-6700K.

opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv