...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: I58b1b41823fa9eb5f37187272e38a2df80c48afb
Reviewed-on: https://gerrit.libreoffice.org/58103
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>