fdo#68849: Add header guards to all include files

added header guards for directories basebmp/, chart2/, cppuhelper/,
include/test/, io/test/, sax/test, shell/, writerfilter/, and xmlhelp/

Change-Id: I0e29a9b75c26d71f58aa98986b52f6d3b46015a6
Reviewed-on: https://gerrit.libreoffice.org/9615
Reviewed-by: Thomas Arnhold <thomas@arnhold.org>
Tested-by: Thomas Arnhold <thomas@arnhold.org>