Remove secondary bidi cursor

The double bidi cursor is not user friendly. Almost no native speaker
of bidi languages likes the double cursor.

Now we always show one cursor.

Change-Id: I249befaf70630bef435c8db9039e8aacf233bf7c
Fixes: 63542996
Test: Manual (no more double cursors, bidi editing feels OK)
Test: bit CtsTextTestCases:*
Test: bit CtsWidgetTestCases:android.widget.cts.EditTextTest
Test: bit CtsWidgetTestCases:android.widget.cts.TextViewTest
Test: bit FrameworksCoreTests:android.text.
Test: bit FrameworksCoreTests:android.widget.EditorCursorTest
Test: bit FrameworksCoreTests:android.widget.TextViewTest