Prevent setting firstRowInViewPort to negative value (#13008)

This should fix MultiSelectWithRemovedRow test in IE.

Change-Id: I54f4ba1cc5c1efeea1582cc0314cfb9a4a859279

client/src/com/vaadin/client/ui/VScrollTable.java

@@ -6965,8 +6965,9 @@ public class VScrollTable extends FlowPanel implements HasWidgets,
         }
 
         firstRowInViewPort = calcFirstRowInViewPort();
-        if (firstRowInViewPort > totalRows - pageLength) {
-            firstRowInViewPort = totalRows - pageLength;
+        int maxFirstRow = totalRows - pageLength;
+        if (firstRowInViewPort > maxFirstRow && maxFirstRow >= 0) {
+            firstRowInViewPort = maxFirstRow;
         }
 
         int postLimit = (int) (firstRowInViewPort + (pageLength - 1) + pageLength