fixed 'rack' version.
backported with 'git diff v3.0.3..v3.0.20 -- test/deprecation_test.rb | patch -p2'
backported from v3.0.20.
backported with 'git diff v3.0.3..v3.0.20 test/time_zone_test.rb | patch -p2'.
backported with 'git diff v3.0.3..v3.0.20 test/controller/integration_test.rb | patch -p2'.
backported with 'git diff v3.0.3..v3.0.20 test/controller/new_base/render_rjs_test.rb | patch -p2'.
backported with 'git diff v3.0.3..v3.0.20 lib/action_view/testing/resolvers.rb | patch -p2'.
fixed test for test_auto_link_with_block_with_html in test/template/text_helper_test.rb.