Change commands to not depend on ARGV

Follow-up to #38463.

This commit changes additional command classes to not depend on prior
ARGV contents.

railties/lib/rails/commands/db/system/change/change_command.rb

@@ -10,8 +10,13 @@ module System
         class ChangeCommand < Base # :nodoc:
           class_option :to, desc: "The database system to switch to."
 
+          def initialize(positional_args, option_args, *)
+            @argv = positional_args + option_args
+            super
+          end
+
           def perform
-            Rails::Generators::Db::System::ChangeGenerator.start
+            Rails::Generators::Db::System::ChangeGenerator.start(@argv)
           end
         end
       end

railties/lib/rails/commands/test/test_command.rb

@@ -29,8 +29,8 @@ def help
       def perform(*)
         $LOAD_PATH << Rails::Command.root.join("test").to_s
 
-        Rails::TestUnit::Runner.parse_options(ARGV)
-        Rails::TestUnit::Runner.run(ARGV)
+        Rails::TestUnit::Runner.parse_options(args)
+        Rails::TestUnit::Runner.run(args)
       end
     end
   end

railties/lib/rails/generators.rb

@@ -123,9 +123,8 @@ def api_only!
           template_engine: nil
         )
 
-        if ARGV.first == "mailer"
-          options[:rails][:template_engine] = :erb
-        end
+        options[:mailer] ||= {}
+        options[:mailer][:template_engine] ||= :erb
       end
 
       # Returns an array of generator namespaces that are hidden.