Remove unused header

Change-Id: Idf069da8098ffdfc5174c161302228076a80b080
Reviewed-on: https://gerrit.libreoffice.org/41673Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tamás Zolnai <tamas.zolnai@collabora.com>

test/source/sheet/datapilotitem.cxx

@@ -15,7 +15,6 @@
 
 #include "cppunit/extensions/HelperMacros.h"
 
-#include <iostream>
 using namespace com::sun::star;
 using namespace com::sun::star::uno;