Make a11y node info parceling more robust

Fix a bug where a malformed Parceled representation
of an AccessibilityNodeInfo could be used to mess with
Bundles as they get reparceled.

Bug: 36491278
Test: Verified that POC no longer works, a11y cts still passes.

(Manual merge from commit 687bb44b)

Change-Id: I7746c9175a2da28f75d4f4b169d7997abadf1852