fix: accumulate all rows in CoreSwtbotTools.tableItems

The loop reassigned the list each iteration, so a table with N rows
returned only the last row. Accumulate instead, matching the javadoc
and the sibling treeItems helper. Empty tables now return an empty
list rather than null.

Author: joaodinissf

com.avaloq.tools.ddk.test.ui/src/com/avaloq/tools/ddk/test/ui/swtbot/CoreSwtbotTools.java

@@ -346,7 +346,7 @@ public static List<SWTBotTableItem> tableItems(final SWTWorkbenchBot bot, final
     waitForTableItem(bot, table);
     List<SWTBotTableItem> items = new ArrayList<SWTBotTableItem>();
     for (int i = 0; i < table.rowCount(); i++) {
-      items = new ArrayList<SWTBotTableItem>(Arrays.asList(table.getTableItem(i)));
+      items.add(table.getTableItem(i));
     }
     return items;
   }