[h2] support empty insert statement (actually used by AR 4.0)

Author: kares

lib/arjdbc/h2/adapter.rb

@@ -148,6 +148,10 @@ def type_to_sql(type, limit = nil, precision = nil, scale = nil)
       end
     end
 
+    def empty_insert_statement_value
+      "VALUES ()"
+    end
+    
     def tables
       @connection.tables(nil, h2_schema)
     end