feat: update workflow files to uniformly distribute the test modules by time taken by each test module (#615)

* fix: lint_setup_py was failing in Kokoro is not fixed

* feat: rearranged test modules in workflow to uniformly distribute the time taken

Author: vi3k6i5

.github/workflows/django_tests_against_emulator0.yml

@@ -29,4 +29,4 @@ jobs:
           GOOGLE_CLOUD_TESTS_CREATE_SPANNER_INSTANCE: true
           RUNNING_SPANNER_BACKEND_TESTS: 1
           SPANNER_TEST_INSTANCE: google-cloud-django-backend-tests
-          DJANGO_TEST_APPS: model_fields model_forms
+          DJANGO_TEST_APPS: admin_changelist admin_ordering aggregation choices distinct_on_fields expressions_window fixtures_model_package datetimes custom_methods generic_inline_admin field_defaults datatypes empty m2o_recursive many_to_one_null migration_test_data_persistence admin_docs invalid_models_tests migrate_signals model_forms.test_uuid model_forms.test_modelchoicefield syndication_tests view_tests update test_utils select_related_onetoone sessions_tests

.github/workflows/django_tests_against_emulator1.yml

@@ -29,4 +29,4 @@ jobs:
           GOOGLE_CLOUD_TESTS_CREATE_SPANNER_INSTANCE: true
           RUNNING_SPANNER_BACKEND_TESTS: 1
           SPANNER_TEST_INSTANCE: google-cloud-django-backend-tests
-          DJANGO_TEST_APPS: mutually_referential nested_foreign_keys null_fk null_fk_ordering null_queries one_to_one ordering order_with_respect_to or_lookups
+          DJANGO_TEST_APPS: db_functions save_delete_hooks get_object_or_404 model_indexes custom_pk indexes transaction_hooks constraints schema custom_columns i18n from_db_value sites_tests mutually_referential model_package defer_regress update_only_fields backends redirects_tests expressions get_or_create foreign_object generic_relations_regress many_to_many select_related generic_relations queryset_pickle model_inheritance