Python: Expand Django 2/3 routing tests with 1.x way

Added it to the `testapp` so it's easy to run the server to SEE that it works.

Added it to `routing_test` so it's obvious this is supported by our modeling
when we _know_ it's running Django 2/3.

python/ql/test/experimental/library-tests/frameworks/django-v2-v3/routing_test.py

@@ -97,3 +97,13 @@ urlpatterns = [
     # We should not report there is a request parameter called `not_valid!`
     path("not_valid/<not_valid!>", not_valid_identifier),  # $routeSetup="not_valid/<not_valid!>"
 ]
+
+# This version 1.x way of defining urls is deprecated in Django 3.1, but still works
+from django.conf.urls import url
+
+def deprecated(request):  # $f-:routeHandler
+    return HttpResponse('deprecated')
+
+urlpatterns = [
+    url(r"^deprecated/", deprecated),  # $f-:routeSetup="^deprecated/"
+]

python/ql/test/experimental/library-tests/frameworks/django-v2-v3/testapp/urls.py

@@ -1,5 +1,8 @@
 from django.urls import path, re_path
 
+# This version 1.x way of defining urls is deprecated in Django 3.1, but still works
+from django.conf.urls import url
+
 from . import views
 
 urlpatterns = [
@@ -8,4 +11,5 @@ urlpatterns = [
     # inline expectation tests (which thinks the `$` would mark the beginning of a new
     # line)
     re_path(r"^ba[rz]/", views.bar_baz),  # $routeSetup="^ba[rz]/"
+    url(r"^deprecated/", views.deprecated),  # $f-routeSetup="^deprecated/"
 ]

python/ql/test/experimental/library-tests/frameworks/django-v2-v3/testapp/views.py

@@ -5,3 +5,6 @@ def foo(request: HttpRequest):  # $routeHandler
 
 def bar_baz(request: HttpRequest):  # $routeHandler
     return HttpResponse("bar_baz")
+
+def deprecated(request: HttpRequest):  # $f-:routeHandler
+    return HttpResponse("deprecated")