array.c: minor performance improvement

* array.c (sort_2): minor performance improvement by replacing
  rb_funcall() with rb_funcallv.

* array.c (rb_ary_bsearch, recursive_cmp, rb_ary_cycle_size): ditto.

* array.c (descending_factorial, binomial_coefficient): ditto.

* array.c (rb_ary_repeated_permutation_size): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43086 b2dd03c8-39d4-4d8f-98ff-823fe69b080e