Always propagate AccessibilityCache events

Bug: b/32642665
Test: Steps:
	- Retrieve root AccessibilityNodeInfo
	- Change text on its child TextView
	- Wait for a few seconds to let the AccessibilityEvent propagate to
    the AccessibilityCache
	- Get the child AccessibilityNodeInfo from the root, corresponding to
    that TextView, and ensure that it's updated to reflect the text
    change
Change-Id: Icbdb91803b646fa06aaf11996d350f6f65c1e809