add a test for [ruby-dev:34524].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@16217 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bootstraptest/test_knownbug.rb

@@ -172,3 +172,8 @@ assert_equal 'ok', %q{
   end
   m
 }, '[ruby-dev:34492]'
+
+assert_normal_exit %q{
+  r = 0**-1
+  r + r
+}, '[ruby-dev:34524]'