Summary:
Original commit changeset: 0b0b3a2d7b80
Reverting D8714400 which removed the `isIPhoneX_deprecated` flag, which is still widely used across the RN codebase https://fburl.com/biggrep/16jg5bzn
Reviewed By: hramos
Differential Revision: D8743401
fbshipit-source-id: cfc44bdd8019eda41e67ca573b20be417d121d12