java(test): fix test names

modules/imgcodecs/misc/java/test/HighguiTest.java → modules/imgcodecs/misc/java/test/ImgcodecsTest.java

-package org.opencv.test.highgui;
+package org.opencv.test.imgcodecs;
 
 import org.opencv.core.MatOfByte;
 import org.opencv.core.MatOfInt;
@@ -6,7 +6,7 @@ import org.opencv.imgcodecs.Imgcodecs;
 import org.opencv.test.OpenCVTestCase;
 import org.opencv.test.OpenCVTestRunner;
 
-public class HighguiTest extends OpenCVTestCase {
+public class ImgcodecsTest extends OpenCVTestCase {
 
     public void testImdecode() {
         fail("Not yet implemented");

modules/videoio/misc/java/test/VideoCaptureTest.java

-package org.opencv.test.highgui;
+package org.opencv.test.videoio;
 
 import java.util.List;