Removed unused code + CommonTestCase.java is Abstract class now

Author: hiteshsondhi88

FFmpegAndroid/src/androidTest/java/com/github/hiteshsondhi88/libffmpeg/CommonTestCase.java

@@ -2,7 +2,7 @@
 
 import junit.framework.TestCase;
 
-public class CommonTestCase extends TestCase {
+public abstract class CommonTestCase extends TestCase {
 
     public void setUp() throws Exception {
         super.setUp();