Add `Style/RedundantFreeze` to remove redudant `.freeze`

Since Rails 6.0 will support Ruby 2.4.1 or higher
`# frozen_string_literal: true` magic comment is enough to make string object frozen.
This magic comment is enabled by `Style/FrozenStringLiteralComment` cop.

* Exclude these files not to auto correct false positive `Regexp#freeze`
 - 'actionpack/lib/action_dispatch/journey/router/utils.rb'
 - 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb'

It has been fixed by https://github.com/rubocop-hq/rubocop/pull/6333
Once the newer version of RuboCop released and available at Code Climate these exclude entries should be removed.

* Replace `String#freeze` with `String#-@` manually if explicit frozen string objects are required

 - 'actionpack/test/controller/test_case_test.rb'
 - 'activemodel/test/cases/type/string_test.rb'
 - 'activesupport/lib/active_support/core_ext/string/strip.rb'
 - 'activesupport/test/core_ext/string_ext_test.rb'
 - 'railties/test/generators/actions_test.rb'

2 files changed, 3 insertions, 3 deletions

diff --git a/actionpack/test/controller/routing_test.rb b/actionpack/test/controller/routing_test.rb
index b97454f1a4..30f2a23b33 100644
--- a/actionpack/test/controller/routing_test.rb
+++ b/actionpack/test/controller/routing_test.rb
@@ -25,8 +25,8 @@ class UriReservedCharactersRoutingTest < ActiveSupport::TestCase
     safe, unsafe = %w(: @ & = + $ , ;), %w(^ ? # [ ])
     hex = unsafe.map { |char| "%" + char.unpack1("H2").upcase }
 
-    @segment = "#{safe.join}#{unsafe.join}".freeze
-    @escaped = "#{safe.join}#{hex.join}".freeze
+    @segment = "#{safe.join}#{unsafe.join}"
+    @escaped = "#{safe.join}#{hex.join}"
   end
 
   def test_route_generation_escapes_unsafe_path_characters
diff --git a/actionpack/test/controller/test_case_test.rb b/actionpack/test/controller/test_case_test.rb
index dda2686a9b..6fc70d6248 100644
--- a/actionpack/test/controller/test_case_test.rb
+++ b/actionpack/test/controller/test_case_test.rb
@@ -542,7 +542,7 @@ XML
   def test_params_passing_with_frozen_values
     assert_nothing_raised do
       get :test_params, params: {
-        frozen: "icy".freeze, frozens: ["icy".freeze].freeze, deepfreeze: { frozen: "icy".freeze }.freeze
+        frozen: -"icy", frozens: [-"icy"].freeze, deepfreeze: { frozen: -"icy" }.freeze
       }
     end
     parsed_params = ::JSON.parse(@response.body)