Nonmoving GC doesn't account for CAF blackholes in "bytes allocated"

The "bytes allocated" metric does not account for blackholes allocated by the mutator during CAF evaluation when the non-moving GC is in use (as they are allocated directly into the nonmoving heap).

The fix is fairly straightforward: nonmovingAllocate should accumulate allocations into cap->total_allocated just as Storage.c:allocate does.