merge revision(s) r45638: [Backport #9518]

	* gc.c (rb_gc_writebarrier): drop special case for big hash/array
	  [Bug #9518]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@45818 b2dd03c8-39d4-4d8f-98ff-823fe69b080e