Add presubmit check for long test names

[austinEng]

Very long test names cause problems on Chrome's infrastructure.
And, long test names probbably imply that the test has been
overparamterized and should be split.

Issue: #

---

Requirements for PR author:

• All missing test coverage is tracked with "TODO" or .unimplemented().
• New helpers are /** documented */ and new helper files are found in helper_index.txt.
• Test behaves as expected in a WebGPU implementation. (If not passing, explain above.)

Requirements for reviewer sign-off:

• Tests are properly located in the test tree.
• Test descriptions allow a reader to "read only the test plans and evaluate coverage completeness", and accurately reflect the test code.
• Tests provide complete coverage (including validation control cases). Missing coverage MUST be covered by TODOs.
• Helpers and types promote readability and maintainability.

When landing this PR, be sure to make any necessary issue status updates.

[ben-clayton]

Nice.

[github-actions]

Previews, as seen when this build job started (fb5b34f):
Run tests | View tsdoc

[Kangz]

Does this presubmit run automatically in Github actions?

[austinEng]

Yes, the actions run grunt pre