Remove the redundant iterable check in the for tag.

Just do it in slice_collection for consistency with the tablerow tag.

lib/liquid/tags/for.rb

@@ -76,9 +76,6 @@ module Liquid
       collection = context.evaluate(@collection_name)
       collection = collection.to_a if collection.is_a?(Range)
 
-      # Maintains Ruby 1.8.7 String#each behaviour on 1.9
-      return render_else(context) unless iterable?(collection)
-
       from = if @from == :continue
         for_offsets[@name].to_i
       else
@@ -189,10 +186,6 @@ module Liquid
     def render_else(context)
       @else_block ? @else_block.render(context) : ''.freeze
     end
-
-    def iterable?(collection)
-      collection.respond_to?(:each) || Utils.non_blank_string?(collection)
-    end
   end
 
   Template.register_tag('for'.freeze, For)

lib/liquid/utils.rb

@@ -8,10 +8,6 @@ module Liquid
       end
     end
 
-    def self.non_blank_string?(collection)
-      collection.is_a?(String) && collection != ''.freeze
-    end
-
     def self.slice_collection_using_each(collection, from, to)
       segments = []
       index = 0
@@ -20,6 +16,7 @@ module Liquid
       if collection.is_a?(String)
         return collection.empty? ? [] : [collection]
       end
+      return [] unless collection.respond_to?(:each)
 
       collection.each do |item|
         if to && to <= index