V575 The potential null pointer is passed into 'foo' function

Add asserts to those cases that are related to OOM cases. There's
nothing to be done if the assertions fail anyway.

Change-Id: I92ac95d44f512aa1948b1552b0e1f6da695a9f92
Reviewed-on: https://gerrit.libreoffice.org/70008
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>