Update checkstyle to 8.10

- fix issues detected
  - YANG custom registrator should be subject to checkstyle
  - fix Java 8 syntax related violations

Change-Id: I0fc52c6612a40d851fd9bc3bf019621776b1f92a
diff --git a/providers/openflow/packet/src/test/java/org/onosproject/provider/of/packet/impl/OpenFlowPacketProviderTest.java b/providers/openflow/packet/src/test/java/org/onosproject/provider/of/packet/impl/OpenFlowPacketProviderTest.java
index 3e42d8f..46305a6 100644
--- a/providers/openflow/packet/src/test/java/org/onosproject/provider/of/packet/impl/OpenFlowPacketProviderTest.java
+++ b/providers/openflow/packet/src/test/java/org/onosproject/provider/of/packet/impl/OpenFlowPacketProviderTest.java
@@ -196,7 +196,7 @@
         return builder.build();
     }
 
-    private static TrafficTreatment treatment(Instruction ... insts) {
+    private static TrafficTreatment treatment(Instruction... insts) {
         TrafficTreatment.Builder builder = DefaultTrafficTreatment.builder();
         for (Instruction i : insts) {
             builder.add(i);
@@ -350,7 +350,7 @@
     private class TestOpenFlowSwitch implements OpenFlowSwitch {
 
         RoleState state;
-        List<OFMessage> sent = new ArrayList<OFMessage>();
+        List<OFMessage> sent = new ArrayList<>();
         OFFactory factory = OFFactoryVer10.INSTANCE;
 
         @Override