ScConditionEntry::Interpret() creates a temporary cell and interprets it
without it actually being in the document at the specified position,
which threading relies upon.

Change-Id: I06fcc11dfbe14e715de4c173e061064ac90da990
Reviewed-on: https://gerrit.libreoffice.org/63182
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>