implemented code review remarks

resolves DEVSIX-1398

Author: joris.schellekens

layout/src/main/java/com/itextpdf/layout/renderer/CollapsedTableBorders.java

@@ -78,7 +78,7 @@ protected CollapsedTableBorders collapseAllBordersAndEmptyRows() {
                 currentRow = rows.get(row);
                 boolean hasCells = false;
                 for (int col = 0; col < numberOfColumns; col++) {
-                    if (null != currentRow && null != currentRow[col]) {
+                    if (null != currentRow[col]) {
                         int colspan = (int) currentRow[col].getPropertyAsInteger(Property.COLSPAN);
                         if (rowspansToDeduct[col] > 0) {
                             int rowspan = (int) currentRow[col].getPropertyAsInteger(Property.ROWSPAN) - rowspansToDeduct[col];