Allow tests in VCR that don't make any API requests

[melinath]

Sometimes we might want to add tests that don't make API requests. Tests like this will not create a VCR test recording, which will cause failures that look like non-determinism (that is, recording "succeeds" but replaying after recording "fails" - because it can't find the (empty) cassette).

While we can skip these tests in VCR, it would be great to allow them so that we can provide greater assurance that they pass.

GoogleCloudPlatform/magic-modules#7973
GoogleCloudPlatform/magic-modules#8460

What kind of contribution is this issue about?

• general contributions

[melinath]

Came up again in GoogleCloudPlatform/magic-modules#10499

[melinath]

There are a number of tests that include the text // Test doesn't interact with API that are also impacted by this. Also ran into this on GoogleCloudPlatform/magic-modules#13422