...which were used by ildc, which is gone since
a8485d558fab53291e2530fd9a1be581c1628deb "[API CHANGE] Remove deprecated idlc
and regmerge from the SDK", and have always been ignored as legacy by its
unoidl-write replacement.

This change has been carried out (making use of GNU sed extensions) with

> for i in $(git ls-files \*.idl); do sed -i -z -E -e 's/\n\n((#[^\n]*\n)+\n)*(#[^\n]*\n)+\n?/\n\n/g' -e 's/\n(#[^\n]*\n)+/\n/g' "$i"; done && git checkout extensions/source/activex/so_activex.idl odk/examples/OLE/activex/so_activex.idl

which apparently happened to do the work.  (The final two files are not UNOIDL
source files.)

Change-Id: Ic9369e05d46e8f7e8a304ab01740b171b92335cd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/135683
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>