Modify backtrace test to take implementations with slightly different...

Modify backtrace test to take implementations with slightly different backtrace output into consideration.

activesupport/test/deprecation_test.rb

@@ -62,7 +62,7 @@ def test_undeprecated
   end
 
   def test_deprecate_class_method
-    assert_deprecated(/none is deprecated.*test_deprecate_class_method at/) do
+    assert_deprecated(/none is deprecated.*test_deprecate_class_method/) do
       assert_equal 1, @dtc.none
     end