Remove redundant conditions of Array#each in ruby extension

mrblib/array.rb

@@ -15,11 +15,9 @@ class Array
     idx, length = -1, self.length-1
     while idx < length and length <= self.length and length = self.length-1
       elm = self[idx += 1]
-      unless elm
       if elm.nil? and length >= self.length
         break
       end
-      end
       block.call(elm)
     end
     self