Copy options before delegating in with_options

cd31e11 switched to passing options as
keyword arguments, which always creates a new hash.

9e4ff29 removed a now-unnecessary call
to `dup`, since the options could no longer be accidentally mutated.

a55620f switched back to passing
options as a positional argument for Ruby < 2.7, but didn't restore the
call to `dup`, which meant that the same options hash was now passed
with every method call and mutations leaked from one call to another.

activesupport/lib/active_support/option_merger.rb

@@ -38,7 +38,7 @@ def invoke_method(method, arguments, options, &block)
         end
       else
         def invoke_method(method, arguments, options, &block)
-          arguments << options if options
+          arguments << options.dup if options
           @context.__send__(method, *arguments, &block)
         end
       end

activesupport/test/option_merger_test.rb

@@ -37,6 +37,12 @@ def test_method_with_options_appends_options_when_options_are_missing
     end
   end
 
+  def test_method_with_options_copies_options_when_options_are_missing
+    with_options(@options) do |o|
+      assert_not_same @options, o.method_with_options
+    end
+  end
+
   def test_method_with_options_allows_to_overwrite_options
     local_options = { hello: "moon" }
     assert_equal @options.keys, local_options.keys