Upgrade CLI, restore prev status check value (#39077)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/39077

Follow-up to https://github.com/facebook/react-native/pull/38988.

- Upgrade to RN CLI `12.0.0-alpha.11`.
- Restore previous value check against `/status` response in test scripts (restored in above CLI alpha).

Changelog: [Internal]

Reviewed By: motiz88

Differential Revision: D48432629

fbshipit-source-id: 175241ad75676281f4638e179873b2ce32f0ea3e