Investigate bucket reallocation during replay

[qpfiffer]

There might be some weirdness happening during replay in regards to bucket allocation. db->val_size might be expanded unnecessarily when:

1. A bucket is reallocated during AOL replay, and
2. That bucket's new value size is less than or equal to it's previous size.

I think you could probably observe this happening if the extent file grew after numerous closings/openings of the database with no actual data change aside from the two conditions above.