Add functionaltiy to clean up Stackdriver metrics.
Add functionaltiy to clean up Stackdriver metrics.

Change-Id: I17183d9ab06f076a20fa8200d0359976f6b2a9a4
Reviewed-on: https://team-review.git.corp.google.com/c/cloud-accelerators-ml/xl-ml-test/+/653205
Reviewed-by: Will Cromar <9dd12cd09dbd89f2974e2a7cca1005dfdecf87da@google.com>

GoogleCloudPlatform/ml-testing-accelerators,GoogleCloudPlatform/ml-testing-accelerators