* Add test case for empty array and first method with args.

Patch by @yui-knk [fix GH-955]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51141 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

enum.c

@@ -828,6 +828,7 @@ static VALUE enum_take(VALUE obj, VALUE n);
  *    %w[foo bar baz].first(2)  #=> ["foo", "bar"]
  *    %w[foo bar baz].first(10) #=> ["foo", "bar", "baz"]
  *    [].first                  #=> nil
+ *    [].first(10)              #=> []
  *
  */