Remove unnecessary explicit generic type declarations

They can be inferred correctly even in Java 7, and display as
compiler warnings in IntelliJ.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=173451087

java/google/registry/monitoring/metrics/MetricReporter.java

@@ -62,7 +62,7 @@ public class MetricReporter extends AbstractScheduledService {
         writeInterval,
         threadFactory,
         MetricRegistryImpl.getDefault(),
-        new ArrayBlockingQueue<Optional<ImmutableList<MetricPoint<?>>>>(1000));
+        new ArrayBlockingQueue<>(1000));
   }
 
   @VisibleForTesting