Use duktape gem as default JS engine on Windows-MINGW and MS-Visual-C builds

The fallback javascript engine on Windows is Windows Script Host (JScript).
However this engine isn't able to process the default assets, because it supports
ES3 only but the coffeescript compiler requires ES5.

Fixes #30014

railties/lib/rails/generators/app_base.rb

@@ -348,6 +348,8 @@ module Rails
         comment = "See https://github.com/rails/execjs#readme for more supported runtimes"
         if defined?(JRUBY_VERSION)
           GemfileEntry.version "therubyrhino", nil, comment
+        elsif RUBY_PLATFORM =~ /mingw|mswin/
+          GemfileEntry.version "duktape", nil, comment
         else
           GemfileEntry.new "mini_racer", nil, comment, { platforms: :ruby }, true
         end

railties/test/generators/app_generator_test.rb

@@ -521,6 +521,8 @@ class AppGeneratorTest < Rails::Generators::TestCase
     run_generator
     if defined?(JRUBY_VERSION)
       assert_gem "therubyrhino"
+    elsif RUBY_PLATFORM =~ /mingw|mswin/
+      assert_gem "duktape"
     else
       assert_file "Gemfile", /# gem 'mini_racer', platforms: :ruby/
     end