Tune test class ancestor (appium#876)

Author: Mykola Mokhnach

src/test/java/io/appium/java_client/ios/ImagesComparisonTest.java

@@ -34,7 +34,7 @@
 import org.junit.Test;
 import org.openqa.selenium.OutputType;
 
-public class ImagesComparisonTest extends BaseIOSTest {
+public class ImagesComparisonTest extends AppIOSTest {
 
  @Test
  public void verifyFeaturesMatching() {