bootstraptest/runner.rb: increase timeout for --jit-wait

because test_io.rb:33 randomly fails
http://ci.rvm.jp/results/trunk-mjit-wait@silicon-docker/1519055

checking MJIT.enabled? on driver might not make sense for target, but as
long as the CI is -DMJIT_FORCE_ENABLE, I believe it works for now.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66344 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bootstraptest/runner.rb

@@ -367,6 +367,7 @@ def assert_normal_exit(testsrc, *rest, timeout: nil, **opt)
 end
 
 def assert_finish(timeout_seconds, testsrc, message = '')
+  timeout_seconds *= 3 if RubyVM::MJIT.enabled? # for --jit-wait
   newtest
   show_progress(message) {
     faildesc = nil