CLDR-15365 add a test for -t-d0 etc. as a warning

[srl295]

CLDR-15191

It turns out there was no test to verify that -t-m0, etc. values were valid. As an example there is latn-t-ethi-m0-ala that should be …-m0-alalc.

As there are existing errors, this only introduces a warning but in the future these should be cleaned up

• [ ] This PR completes the ticket.

[jira-pull-request-webhook[bot]]

Hooray! The files in the branch are the same across the force-push. 😃

~ Your Friendly Jira-GitHub PR Checker Bot

[srl295]

There is a thorough validity checker somewhere else. that should be used.

Hmm. Do you know where ? It didn't seem to fail on invalid bcp47 tags.

[srl295]

There is a thorough validity checker somewhere else. that should be used. Hmm. Do you know where ? It didn't seem to fail on invalid bcp47 tags.

@macchiati did not find another validity checker, do you know where it is?