test/ruby/test_optimization.rb: increase timeout

For slow systems...

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63798 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_optimization.rb

@@ -707,7 +707,7 @@ class TestRubyOptimization < Test::Unit::TestCase
   end
 
   def test_clear_unreachable_keyword_args
-    assert_separately [], <<-END, timeout: 20
+    assert_separately [], <<-END, timeout: 30
       script =  <<-EOS
         if true
         else