...by removing explicitly user-provided functions that do the same as their
implicitly-defined counterparts, but may prevent implicitly declared copy
functions from being defined as non-deleted in the future

Change-Id: Idd25cd86db429b0f3391e359bb2617863b29eb67
Reviewed-on: https://gerrit.libreoffice.org/58053
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>