fix Can select text by dragging with a mouse due to dragStart only being fired on the first PointerMoveEvent, the previous pan gesture recognizer would fire both dragStart and dragUpdate

Author: Renzo Olivares

packages/flutter/test/material/text_field_test.dart

@@ -1980,10 +1980,13 @@ void main() {
     await skipPastScrollingAnimation(tester);
 
     final Offset ePos = textOffsetToPosition(tester, testValue.indexOf('e'));
+    final Offset fPos = textOffsetToPosition(tester, testValue.indexOf('f'));
     final Offset gPos = textOffsetToPosition(tester, testValue.indexOf('g'));
 
     final TestGesture gesture = await tester.startGesture(ePos, kind: PointerDeviceKind.mouse);
     await tester.pump();
+    await gesture.moveTo(fPos);
+    await tester.pump();
     await gesture.moveTo(gPos);
     await tester.pump();
     await gesture.up();