Don't copy NoCopySpans for assist and autofill

For AssistStructure, and AutofillValue, create a copy of the text in 
setText and forText methods if it is a Spanned.

Fixes: 36838999
Test: cts-tradefed run cts -m CtsAutoFillServiceTestCases
Test: cts-tradefed run cts -m CtsAssistTestCases
Test: cts-tradefed run cts --test android.widget.cts.TextViewTest -m \
      CtsWidgetTestCases

Change-Id: I52e780fa9baa17c375d3945dc714171f41fd7db5