Fix rendering of MultiPolygon text styles

When overflow is false and some of a MultiPolygon's polygons are
outside the rendered extent the coordinates and geometryWidths arrays are
not kept in sync. Therefore the width check will filter on wrong data and
some texts may not be rendered.

src/ol/render/canvas/TextBuilder.js

@@ -232,7 +232,7 @@ class CanvasTextBuilder extends CanvasBuilder {
       }
       this.endGeometry(feature);
     } else {
-      const geometryWidths = textState.overflow ? null : [];
+      let geometryWidths = textState.overflow ? null : [];
       switch (geometryType) {
         case GeometryType.POINT:
         case GeometryType.MULTI_POINT:
@@ -275,6 +275,21 @@ class CanvasTextBuilder extends CanvasBuilder {
       if (end === begin) {
         return;
       }
+      if (
+        geometryWidths &&
+        (end - begin) / 2 !== flatCoordinates.length / stride
+      ) {
+        let beg = begin / 2;
+        geometryWidths = geometryWidths.filter((w, i) => {
+          const keep =
+            coordinates[(beg + i) * 2] === flatCoordinates[i * stride] &&
+            coordinates[(beg + i) * 2 + 1] === flatCoordinates[i * stride + 1];
+          if (!keep) {
+            --beg;
+          }
+          return keep;
+        });
+      }
 
       this.saveTextStates_();