array.c: use shared array in rb_ary_slice
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37583 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
array.c: use shared array in rb_ary_slice
[Feature #6638]
end of array, cause rb_ary_concat use rb_ary_slice.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37583 b2dd03c8-39d4-4d8f-98ff-823fe69b080e