Fix indexing issue in Compatibility Grid resize when scrolled to bottom. (#12003)

Issue #11893, cherry-pick from #11984

compatibility-client/src/main/java/com/vaadin/v7/client/widgets/Escalator.java

@@ -3720,6 +3720,7 @@ public class Escalator extends Widget
                                 visualRowOrder.getLast()) + 1;
                         moveAndUpdateEscalatorRows(Range.withOnly(0),
                                 visualRowOrder.size(), newLogicalIndex);
+                        updateTopRowLogicalIndex(1);
                     }
                 }
             }

uitest/src/main/java/com/vaadin/tests/components/grid/CompatibilityGridScrollDownResize.java

@@ -0,0 +1,34 @@
+package com.vaadin.tests.components.grid;
+
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.tests.minitutorials.v7_4.GridExampleHelper;
+import com.vaadin.ui.VerticalLayout;
+import com.vaadin.v7.ui.Grid;
+
+public class CompatibilityGridScrollDownResize extends AbstractTestUI {
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        // container with at least 100 rows
+        final Grid grid = new Grid(GridExampleHelper.createContainer());
+        grid.setSizeFull();
+        addComponent(grid);
+        getLayout().setSizeFull();
+        getLayout().setExpandRatio(grid, 2);
+        ((VerticalLayout) getLayout().getParent()).setSizeFull();
+    }
+
+    @Override
+    protected Integer getTicketNumber() {
+        return 11893;
+    };
+
+    @Override
+    protected String getTestDescription() {
+        return "Scrolling all the way down, resizing the browser window smaller "
+                + "so that one row gets completely hidden, and scrolling down "
+                + "again should keep the row contents consistent and in expected "
+                + "sequence.";
+    }
+}