Work around Pharo 6.0 bug
Work around Pharo 6.0 bug

Pharo 6.0 still has format 0 objects that actually do have inst vars.
This was claimed fixed at
https://pharo.fogbugz.com/f/cases/19010/ImmediateLayout-and-EphemeronLay
out-have-wrong-object-format but the instances themselves still have
the 0 format code. Only the classes were fixed, but the objects were
not re-created.

We now work around this by ignoring the format code and relying on the
object size to tell us how many inst vars there are actually.

bertfreudenberg/SqueakJS,bertfreudenberg/SqueakJS,bertfreudenberg/SqueakJS,bertfreudenberg/SqueakJS