Use Arrays.hashCode() instead of Object.hashCode()

Explanation:
https://github.com/google/error-prone/blob/master/docs/bugpattern/ArrayHashCode.md

message_generation/src/main/java/org/ros/internal/message/field/BooleanArrayField.java

@@ -94,7 +94,7 @@ public class BooleanArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }
 

message_generation/src/main/java/org/ros/internal/message/field/ByteArrayField.java

@@ -94,7 +94,7 @@ public class ByteArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }
 

message_generation/src/main/java/org/ros/internal/message/field/DoubleArrayField.java

@@ -94,7 +94,7 @@ public class DoubleArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }
 

message_generation/src/main/java/org/ros/internal/message/field/FloatArrayField.java

@@ -94,7 +94,7 @@ public class FloatArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }
 

message_generation/src/main/java/org/ros/internal/message/field/IntegerArrayField.java

@@ -94,7 +94,7 @@ public class IntegerArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }
 

message_generation/src/main/java/org/ros/internal/message/field/LongArrayField.java

@@ -96,7 +96,7 @@ public class LongArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }
 

message_generation/src/main/java/org/ros/internal/message/field/ShortArrayField.java

@@ -94,7 +94,7 @@ public class ShortArrayField extends Field {
   public int hashCode() {
     final int prime = 31;
     int result = super.hashCode();
-    result = prime * result + ((value == null) ? 0 : value.hashCode());
+    result = prime * result + ((value == null) ? 0 : Arrays.hashCode(value));
     return result;
   }