Allow forms to skip hydration of hidden inputs (#26735)

Summary:
This allows us to emit extra ephemeral data that will only be used on
server rendered forms.

First I refactored the shouldSkip functions to now just do that work
inside the canHydrate methods. This makes the Config bindings a little
less surface area but it also helps us optimize a bit since we now can
look at the code together and find shared paths.

canHydrate returns the instance if it matches, that used to just be
there to refine the type but it can also be used to just return a
different instance later that we find. If we don't find one, we'll bail
out and error regardless so no need to skip past anything.

DiffTrain build for commit facebook/react@67f4fb0.

Changelog: [Internal]

<< DO NOT EDIT BELOW THIS LINE >>

Reviewed By: sammy-SC

Differential Revision: D45453502

Pulled By: tyao1

fbshipit-source-id: 1ac34bcc2d59fdbfbc25e51f6bd5354777a33f96

packages/react-native/Libraries/Renderer/REVISION

@@ -1 +1 @@
-8ea96ef84d8f08ed1846dec9e8ed20d2225db0d3
+67f4fb02130b1fe1856289e3b66bb0b8cca57ff7