output more verbose to debug

following failure insists unexpected condition
http://c5664.rubyci.org/~chkbuild/ruby-trunk/log/20140515T133301Z.diff.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45989 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_thread.rb

@@ -792,12 +792,13 @@ _eom
   end
 
   def test_main_thread_status_at_exit
-    assert_in_out_err([], <<-INPUT, %w(false), [])
+    assert_in_out_err([], <<-'INPUT', ["false false aborting"], [])
 Thread.new(Thread.current) {|mth|
   begin
     Thead.pass until mth.stop?
+    p :mth_stopped # don't run if killed by rb_thread_terminate_all
   ensure
-    p mth.alive?
+    puts "#{mth.alive?} #{mth.status} #{Thread.current.status}"
   end
 }
     INPUT