manta: remove need for baselines

The old tests used them, but the files don't actually exist, so I'm
assuming they're not actually used.

Change-Id: I6d4f78558c325b085f248567f59c54789389cab3
test: add a baseline

Change-Id: Ib48d8ea18dafe70d397680294c455f28b418f89c
Merge topic 'use-external-data' into next

3cccff24 test: add a baseline
baad4a68 manta: remove need for baselines