test_runner: support describe / it only shorthands #46562

What is the problem this feature will solve?

A common shorthand when writing tests is to be able to quickly run isolated blocks of tests using describe.only and it.only.

Examples

• https://jestjs.io/docs/api#describeonlyname-fn
• https://jestjs.io/docs/api#testonlyname-fn-timeout (alias to it.only)
• https://vitest.dev/api/#describe-only
• https://vitest.dev/api/#test-only (alias to it.only)

Currently the test runner doesn't support these shorthands.

• TypeError: describe.only is not a function
• error: 'it.only is not a function'

What is the feature you are proposing to solve the problem?

Use a consistent approach with the other describe/it shorthands (skip and todo) and add another for only.

What alternatives have you considered?

No response