fix equality bug for lineString

lib/src/turf_equality_base.dart

@@ -133,7 +133,7 @@ class Equality {
             line1.coordinates.first, newLine.coordinates.first)) {
           return false;
         } else {
-          _compareLine(line1, newLine);
+          return _compareLine(line1, newLine);
         }
       }
     } else {

test/context/helper.dart

@@ -0,0 +1,25 @@
+import 'package:turf/helpers.dart';
+
+LineString lineString(List<List<int>> coordinates) {
+  return LineString(coordinates: coordinates.toPositions());
+}
+
+Point point(List<double> coordinates) {
+  return Point(coordinates: Position.of(coordinates));
+}
+
+Feature<Polygon> polygon(List<List<List<int>>> coordinates) {
+  return Feature(
+    geometry: Polygon(coordinates: coordinates.toPositions()),
+  );
+}
+
+extension PointsExtension on List<List<int>> {
+  List<Position> toPositions() =>
+      map((position) => Position.of(position)).toList(growable: false);
+}
+
+extension PolygonPointsExtensions on List<List<List<int>>> {
+  List<List<Position>> toPositions() =>
+      map((element) => element.toPositions()).toList(growable: false);
+}