Organization module end-to-end tests (#1860)

* added tag serial to mark tests to be run serially
* always run tests using loadgroup distribution to make use of serial tag
* added end-to-end tests for organization, not adding to custom constraints as the name has to be unique
* fixed granting custom roles created in the same module call

tests/modules/organization/examples/logging.yaml

@@ -47,7 +47,7 @@ values:
     name: notice
     org_id: '1122334455'
   module.org.google_logging_organization_sink.sink["warnings"]:
-    destination: storage.googleapis.com/gcs_sink
+    destination: storage.googleapis.com/test-gcs_sink
     disabled: false
     exclusions: []
     filter: severity=WARNING