Update chapter9-exercise-ids-tests.md to make more insensitive to dukpy version

tests/chapter9-exercise-ids-tests.md

@@ -87,7 +87,7 @@ Replace the id with something that has a different id.
     Traceback (most recent call last):
       ...
     _dukpy.JSRuntimeError: ReferenceError: identifier 'one' undefined
-        at [anon] (duk_js_var.c:1239) internal
+      ...
         at eval (eval:1) preventsyield
     >>> js.run("replacement;")
     {'handle': 2}
@@ -110,19 +110,19 @@ Empty the document of ids.
     Traceback (most recent call last):
       ...
     _dukpy.JSRuntimeError: ReferenceError: identifier 'alice' undefined
-        at [anon] (duk_js_var.c:1239) internal
+      ...
         at eval (eval:1) preventsyield
     >>> js.run("one;")
     Traceback (most recent call last):
       ...
     _dukpy.JSRuntimeError: ReferenceError: identifier 'one' undefined
-        at [anon] (duk_js_var.c:1239) internal
+      ...
         at eval (eval:1) preventsyield
     >>> js.run("replacement;")
     Traceback (most recent call last):
       ...
     _dukpy.JSRuntimeError: ReferenceError: identifier 'replacement' undefined
-        at [anon] (duk_js_var.c:1239) internal
+      ...
         at eval (eval:1) preventsyield
     >>> browser.print_tree(this_browser.active_tab.document)
      DocumentLayout()