More aggressive Clang 13 trunk -Werror,-Wdeprecated-copy[-with-dtor]

...since
<abf3ca61e3>
"[Diagnostics] Restore -Wdeprecated warning when user-declared copy assignment
operator is defined as deleted (PR45634)"

Change-Id: I43ae8a620915ad211a1f21ecf89b6955b7d2faaf
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/114674
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

compilerplugins/clang/test/buriedassign.cxx

@@ -43,6 +43,7 @@ struct MyInt
         : x(i)
     {
     }
+    MyInt(MyInt const&) = default;
     MyInt& operator=(MyInt const&) = default;
     MyInt& operator=(int) { return *this; }
     bool operator<(MyInt const& other) const { return x < other.x; }