Remove unused promiseRejectionIsError
Remove unused promiseRejectionIsError

Summary: Changelog: [Internal]

Reviewed By: MichaReiser

Differential Revision: D26338073

fbshipit-source-id: 7b4d8881ffc58ee93b1ccf58e6717a4a8597dece

facebook/react-native,pandiaraj44/react-native,arthuralee/react-native,javache/react-native,myntra/react-native,facebook/react-native,arthuralee/react-native,javache/react-native,janicduplessis/react-native,janicduplessis/react-native,arthuralee/react-native,janicduplessis/react-native,myntra/react-native,pandiaraj44/react-native,pandiaraj44/react-native,facebook/react-native,javache/react-native,facebook/react-native,pandiaraj44/react-native,janicduplessis/react-native,pandiaraj44/react-native,javache/react-native,javache/react-native,arthuralee/react-native,myntra/react-native,myntra/react-native,janicduplessis/react-native,janicduplessis/react-native,pandiaraj44/react-native,facebook/react-native,facebook/react-native,pandiaraj44/react-native,pandiaraj44/react-native,javache/react-native,javache/react-native,javache/react-native,myntra/react-native,myntra/react-native,javache/react-native,arthuralee/react-native,myntra/react-native,facebook/react-native,myntra/react-native,janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,myntra/react-native,facebook/react-native