issue(spl): ptr cast from `std::cell::Cell<isize>` to `I64`

[Stevengre]

#traverseProjection ( toLocal ( 13 ) , thunk ( #cast ( PtrLocal ( 3 , place ( ... local: local ( 15 ) , projection: projectionElemField ( fieldIdx ( 2 ) , ty ( 5900105 ) )  projectionElemField ( fieldIdx ( 0 ) , ty ( 2800120 ) )  projectionElemField ( fieldIdx ( 0 ) , ty ( 2800121 ) )  .ProjectionElems ) , mutabilityNot , metadata ( noMetadataSize , 0 , noMetadataSize ) ) , castKindPtrToPtr , ty ( 2800137 ) , ty ( 2800122 ) ) ) , projectionElemDeref  .ProjectionElems , .Contexts )

Type 2800137: PtrT(pointee_type=2800121)
Type 2800122: PtrT(pointee_type=2800078)

Type 2800121: StructT(name='std::cell::UnsafeCell<isize>', adt_def=2800042, fields=[2800078], layout=LayoutShape(fields=ArbitraryFields(offsets=[MachineSize(num_bits=0)]), variants=Single(index=0), abi=ValueAbi(), abi_align=8, size=MachineSize(num_bits=64)))
Type 2800078: IntT(info=<IntTy.I64: 8>)

[Stevengre]

This is related to concrete execution and will not encounter with cheatcode.