Fix incrementing before mmap success check

[devarajabc]

Move list->size increment after the mmap failure check.
After mmap fails and returns 0, list->size has already been permanently incremented.
On the next call to AllocDynarecMap, this loop iterates up to the new list->size,
hitting the uninitialized list->chunks[i].

[ptitSeb]

I understand the issue, but this was done that way to help with mutli-threaded access and avoid having competition when initializing the new list. Not sure this fix will handle heavy multi-threading well.

[ptitSeb]

It would be safer to do the int i = list->size++; to after the potential point of failure, and just use list->size when trying to get the map size as it's readonly and not a critical information anyway.

[devarajabc]

I see, you are right. The mmap failure path is nearly impossible to hit in practice. It's not worth it

[devarajabc]

Maybe I can add a comment for it.