Refactor code to make it more clear

Extract the conditional to a method that explains what it needs to do.

Also avoid calling `present?`.

Author: rafaelfranca

activerecord/lib/arel/visitors/to_sql.rb

@@ -979,7 +979,7 @@ def infix_value_with_paren(o, collector, value, suppress_parens = false)
 
         # Used by some visitors to enclose select queries in parentheses
         def grouping_parentheses(o, collector, always_wrap_selects = true)
-          if o.is_a?(Nodes::SelectStatement) && (always_wrap_selects || o.orders.present? || o.limit.present? || o.offset.present?)
+          if o.is_a?(Nodes::SelectStatement) && (always_wrap_selects || require_parentheses?(o))
             collector << "("
             visit o, collector
             collector << ")"
@@ -989,6 +989,10 @@ def grouping_parentheses(o, collector, always_wrap_selects = true)
           end
         end
 
+        def require_parentheses?(o)
+          !o.orders.empty? || o.limit || o.offset
+        end
+
         def aggregate(name, o, collector)
           collector << "#{name}("
           if o.distinct