I noted the the current VMs don't handle the case of storing
−2,147,483,648 (primitive failure) via signed32BitValueOf: usually
called via FFI signedLongAt:put:
For plugin writers who used signed64BitValueOf: (primitive failure)
and signed64BitIntegerFor: returned zero if passed
signed64BitIntegerFor: is the one that is nasty since your value of
0x8000000000000000 silently turns in 0.