Fix TextView#setTextCursorDrawable for resid=0

The CL fixes TextView#setTextCursorDrawable, for the case when a zero
drawable resource id is passed. We want to set a null Drawable, but the
Context#getDrawable(0) call was throwing rather than returning null.

Bug: 122742983
Test: atest CtsWidgetTestCases:android.widget.cts.TextViewTest
Change-Id: I45bf57002043d7dbe541d76e61fce3f729959fc8

core/java/android/widget/TextView.java

@@ -3685,7 +3685,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
      * @attr ref android.R.styleable#TextView_textCursorDrawable
      */
     public void setTextCursorDrawable(@DrawableRes int textCursorDrawable) {
-        setTextCursorDrawable(mContext.getDrawable(textCursorDrawable));
+        setTextCursorDrawable(
+                textCursorDrawable != 0 ? mContext.getDrawable(textCursorDrawable) : null);
     }
 
     /**