...where necessary, so the tests will succeed if SRCDIR is a read-only tree.

Change-Id: Iea4c52d5982d3eba079088ef1670ff557ce30c3f
Reviewed-on: https://gerrit.libreoffice.org/52122Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>