It makes sense to kill threads after 3 minutes in dbgutils mode for unittests,
but this also meant that e.g. threaded Calc calculations in a gdb session
or when ran in Valgrind sometimes asserted halfway through the calculation.

Change-Id: I4fdd82549909feda9d4461b64eba0fcdca8be9be
Reviewed-on: https://gerrit.libreoffice.org/70422
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>