Add extra logging to cancellable test.

Author: ioquatix

test/io/event/selector/cancellable.rb

@@ -33,6 +33,7 @@
 			reader.transfer
 
 			while reader.alive?
+				$stderr.puts "Sending interrupt to fiber: #{reader}", reader.backtrace
 				reader.raise(Interrupt)
 				selector.select(0)
 			end