Clean up packages and cocoon tests

[Piinks]

• Removed the flutter/packages test registry, as these tests are already run in flutter/flutter here: https://ci.chromium.org/ui/p/flutter/builders/try/Linux%20flutter_plugins
• Updated the flutter/cocoon hash while I was here. It had not been updated in ~2 years

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[stuartmorgan-g]

• Removed the flutter/packages test registry, as these tests are already run in flutter/flutter here: https://ci.chromium.org/ui/p/flutter/builders/try/Linux%20flutter_plugins

That shard only runs analyze. The customer tests run actual tests from several packages, so this will remove coverage.

If you just want to remove the duplicate analysis, you'd need to remove the analyze steps from the customer test script in the packages repo, rather that removing the entire customer testing call.

[Piinks]

• Removed the flutter/packages test registry, as these tests are already run in flutter/flutter here: ci.chromium.org/ui/p/flutter/builders/try/Linux%20flutter_plugins

That shard only runs analyze. The customer tests run actual tests from several packages, so this will remove coverage.

If you just want to remove the duplicate analysis, you'd need to remove the analyze steps from the customer test script in the packages repo, rather that removing the entire customer testing call.

Ah ha! Ok that answers a question I had about whether or not material_ui and cupertino_ui tests were running in presubmit in flutter/flutter already. Sounds like no, since the test hash here is 6 months old, and the luci build is only for analyze. Ok cool. I will update this to just update the hash rather than remove altogether.