Increase timeout of TestRequire#test_require_with_loaded_features_pop

unstable10s fails it because of timeout
http://rubyci.s3.amazonaws.com/unstable10s/ruby-trunk/log/20161201T161908Z.fail.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56982 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_require.rb

@@ -697,7 +697,7 @@ class TestRequire < Test::Unit::TestCase
     bug7530 = '[ruby-core:50645]'
     Tempfile.create(%w'bug-7530- .rb') {|script|
       script.close
-      assert_in_out_err([{"RUBYOPT" => nil}, "-", script.path], <<-INPUT, %w(:ok), [], bug7530)
+      assert_in_out_err([{"RUBYOPT" => nil}, "-", script.path], <<-INPUT, %w(:ok), [], bug7530, timeout: 20)
         PATH = ARGV.shift
         THREADS = 2
         ITERATIONS_PER_THREAD = 1000