Introduce feature flag for safer main queue sync dispatch
Summary: Gating for "safer main queue sync dispatch": D74769326
Changelog: [Internal]
Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
This pull request was exported from Phabricator. Differential Revision: D74940621
Merged as https://github.com/facebook/react-native/commit/19d7e40c97a18c5628b2cc0a7fe4b2c24b464c82