Summary:
Allow JS to keep track of mostRecentEventCount and pass it into each event or prop update. We really don't want to separately keep track of that data.
In non-Fabric, the ShadowNode will keep track of the mostRecentEventCount associated to prop updates. In Fabric, that happens on the C++ ShadowNode.
Changelog: [Internal] Simplification to TextInput native state
Reviewed By: mdvacca
Differential Revision: D20374573
fbshipit-source-id: 385fba6ec69a071c78832a686b397699a6c55d67