Show how many seconds it timeouts

By this we can easily extend timeout.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61626 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/lib/envutil.rb

@@ -147,7 +147,7 @@ module EnvUtil
       stderr = stderr_filter.call(stderr) if stderr_filter
       if timeout_error
         bt = caller_locations
-        msg = "execution of #{bt.shift.label} expired"
+        msg = "execution of #{bt.shift.label} expired timeout (#{timeout} sec)"
         msg = Test::Unit::Assertions::FailDesc[status, msg, [stdout, stderr].join("\n")].()
         raise timeout_error, msg, bt.map(&:to_s)
       end