Revert "Scale sleeping times"

This reverts commit e57d619421.

Test fails:
http://ci.rvm.jp/results/trunk-gc-asserts@ruby-sky1/2518563
http://ci.rvm.jp/results/trunk-gc_compact@silicon-docker/2518533

test/io/wait/test_io_wait.rb

@@ -164,8 +164,4 @@ private
       return written
     end while true
   end
-
-  def sleep(time)
-    super EnvUtil.apply_timeout_scale(time)
-  end
 end if IO.method_defined?(:wait)