sanity_checks: add error messages to have_same_provides test

[cjmayo]

No description provided.

[bgilbert]

Thanks. For dependency_names, releases.json must match the sum of the wrap file's dependency_names and any transitional provides in the wrap file. We no longer allow transitional provides for ports, but we do allow them for upstream projects that directly provide a Meson config.

[cjmayo]

Oops, it is even clearly named get_transitional_provides(). Updated.

[bgilbert]

Thanks!