...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: I4da623b67ef1792f9dd04382dcb0e772d66bdb40
Reviewed-on: https://gerrit.libreoffice.org/58104
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>