<https://cplusplus.github.io/LWG/issue3320> "span::cbegin/cend methods produce
different results than std::[ranges::]cbegin/cend", as implemented now in
<https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;a=commit;
h=247f410b83797a1840573840cc2a539ef9d7f96b> "libstdc++: Remove std::span::cbegin
and std::span::cend (LWG 3320)".
Turns out we only used the removed member functions in o3tl/qa/test-span.cxx.
Change-Id: I6c73797594b4e0e753a88840033d54961e271df5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/89261
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
