New fix for popup behavior in AutoCompleteTextViews.

Bug 3374144

The fix in https://android-git.corp.google.com/g/#change,91880 is not
sufficient. An updated adapter needs to be able to force an update of
the poup result list.

Addded a flag that prevents the popup from being re-opened when it has
previously been closed by a user action.

Change-Id: I45fab056c8ebd6dc4317430213f2bc37b51b79e3