Correct spelling of "roundtrip" `test_group`

[mjherzog]

The current spelling of the 'roundtrip' test_group name is incorrect because the adjectival form of "roundtrip" is "round-trip" - see https://www.merriam-webster.com/dictionary/roundtrip.
We need to update the PURL test schema and automate updates for all existing PURL test files.
This issue supersedes:

• Use proper spelling of the wording "round trip" #543