testing: start using btlr [(#3959)](GoogleCloudPlatform/python-docs-samples#3959)

* testing: start using btlr

The binary is at gs://cloud-devrel-kokoro-resources/btlr/v0.0.1/btlr

* add period after DIFF_FROM

* use array for btlr args

* fix websocket tests

* add debug message

* wait longer for the server to spin up

* dlp: bump the wait timeout to 10 minutes

* [run] copy noxfile.py to child directory to avoid gcloud issue

* [iam] fix: only display description when the key exists

* use uuid4 instead of uuid1

* [iot] testing: use the same format for registry id

* Stop asserting Out of memory not in the output

* fix missing imports

* [dns] testing: more retries with delay

* [dlp] testing: longer timeout

* use the max-concurrency flag

* use 30 workers

* [monitoring] use multiple projects

* [dlp] testing: longer timeout

Author: Takashi Matsuo

samples/api-client/manager/manager_test.py

@@ -41,7 +41,7 @@
 pubsub_topic = 'projects/{}/topics/{}'.format(project_id, topic_id)
 
 # This format is used in the `clean_up_registries()` below.
-registry_id = 'test-registry-{}-{}'.format(uuid.uuid1(), int(time.time()))
+registry_id = 'test-registry-{}-{}'.format(uuid.uuid4().hex, int(time.time()))
 
 
 @pytest.fixture(scope="session", autouse=True)