Enable KafkaItemReaderTests

These tests were temporarily disabled, see 85a9cad.
Now that spring-projects/spring-kafka#2342
is fixed, these tests are re-enabled again.

Author: fmbenhassine

spring-batch-infrastructure/src/test/java/org/springframework/batch/item/kafka/KafkaItemReaderTests.java

@@ -32,7 +32,6 @@
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.ClassRule;
-import org.junit.Ignore;
 import org.junit.Test;
 
 import org.springframework.batch.item.ExecutionContext;
@@ -55,7 +54,6 @@
  * @author Mathieu Ouellet
  * @author Mahmoud Ben Hassine
  */
-@Ignore // FIXME https://github.com/spring-projects/spring-kafka/pull/2342
 public class KafkaItemReaderTests {
 
 	@ClassRule