Summary:
This diff disables accessibility state changes of the focused view for Android API < 21.
This is necessary because the method view.isAccessibilityFocused was introduced in Android API 21
Users in Android API < 21 will not be able to hear accessibility state changes of the focused view (feature introduced by D17903205)
Changelog: disables accessibility state changes of the focused view for Android API < 21, see PR: 26624
Reviewed By: fkgozali
Differential Revision: D19199096
fbshipit-source-id: 12b349f0ac94b77e9e7328ae40e1ae1a278e8b24