which can result from division by zero in earlier code, rather assert
explicitly than suffer from weird very large sal_Int64 values (which is
what NaN converts to, if we let it do the implicit conversion)
Change-Id: Id059b84906bbc90a4fa51489ca96dc0267bb9342
Reviewed-on: https://gerrit.libreoffice.org/42798
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>