Add test for multi-argument break in blocks

Author: mame

scenario/known-issues/multi_arg_break.rb scenario/control/multi_arg_break.rbscenario/known-issues/multi_arg_break.rb renamed to scenario/control/multi_arg_break.rb

@@ -10,3 +10,6 @@ def check
 # retry
 
 ## assert
+class Object
+  def check: -> (Integer | [:a, :b, :c])
+end