Remove [] handling in AppEngineRule

It's not in use by anything anymore.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=213293960

javatests/google/registry/testing/AppEngineRule.java

@@ -120,7 +120,6 @@ public final class AppEngineRule extends ExternalResource {
       return this;
     }
 
-
     /** Turn on the task queue service. */
     public Builder withTaskQueue() {
       return withTaskQueue(QUEUE_XML);