Fix size on Enumerable#cycle when the size is 0 [Bug #14082].

	Patch by Kenichi Kamiya

	test/ruby/test_lazy_enumerator.rb: test for [Bug #14082]

	enum.c: check argument first

	* enum.c (enum_cycle_size): check an argument before the size of
	  the receiver, if it is given.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@62782 b2dd03c8-39d4-4d8f-98ff-823fe69b080e