hash.c: detect recursion for all

* hash.c (rb_hash): detect recursion for all `hash' methods.  each
  `hash' methods no longer need to use rb_exec_recursive().

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43980 b2dd03c8-39d4-4d8f-98ff-823fe69b080e