Switching to the isIntegerValue check used in the SqueakVM
Switching to the isIntegerValue check used in the SqueakVM

- this switch is mainly done to be in sync with Squeak on such important details, if it breaks somewhere relevant, it is likely that the Squeak folks will also encounter it

Signed-off-by: Stefan Marr <46f1a0bd5592a2f9244ca321b129902a06b53e03@stefan-marr.de>

smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM,smarr/OmniVM