Do not linkify text with RLO/LRO characters.

Also don't show smart actions for selections in text with unsupported
characters.

Bug: 116321860
Test: atest android.view.textclassifier.TextClassifierTest \
            android.text.util.cts.LinkifyTest \
	    android.text.util.LinkifyTest \
	    android.widget.TextViewActivityTest

Change-Id: Id271cab8aef6b9b13ef17f1a8654c7616f75cf13