Use Signal.signame instead of Signal.list.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56620 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_optimization.rb

@@ -342,7 +342,7 @@ EOS
       *, stat = Process.wait2(pid)
       [stat, err_p.read]
     }
-    assert_equal(Signal.list["INT"], status.termsig)
+    assert_equal("INT", Signal.signame(status.termsig))
     assert_match(/Interrupt/, err, bug)
   end