Summary:
Now RCTTextInput relies on ivar to detect should it reconstruct inputAccessoryView or not.
Previously we checked `inputAccessoryView` directly which breaks some 3rd party libs.
See https://github.com/facebook/react-native/issues/16071 for more details.
cc douglasjunior
Reviewed By: javache
Differential Revision: D5994798
fbshipit-source-id: c086efdd24f5528393a4c734ff7c984e0ed740d1