chore: Rename the IT class to use IT as the prefix

Author: lqiu96

…/DatastoreBuiltInAndCustomMetricsIT.java …/ITDatastoreBuiltInAndCustomMetrics.javajava-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/DatastoreBuiltInAndCustomMetricsIT.java renamed to java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/ITDatastoreBuiltInAndCustomMetrics.java java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/DatastoreBuiltInAndCustomMetricsIT.java renamed to java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/ITDatastoreBuiltInAndCustomMetrics.java

@@ -84,7 +84,7 @@
  */
 @RunWith(JUnit4.class)
 @SuppressWarnings("checkstyle:abbreviationaswordinname")
-public class DatastoreBuiltInAndCustomMetricsIT {
+public class ITDatastoreBuiltInAndCustomMetrics {
 
   private static final String PROJECT_ID = System.getenv("GOOGLE_CLOUD_PROJECT");
   private static final String DATABASE_ID =