Remove duplicated lines

exercises/hello-world/build.gradle

     events = ["passed", "failed", "skipped"]
   }
 }
-test {
-  testLogging {
-    exceptionFormat = 'full'
-    events = ["passed", "failed", "skipped"]
-  }
-}

exercises/hello-world/src/test/java/HelloWorldTest.java

 import org.junit.Test;
 import org.junit.Ignore;
-import org.junit.Ignore;
 
 import static org.junit.Assert.assertEquals;