Wrap the SerializationRecord (Vector<u8, 1024>) in an OwnPtr so that
each ObjectStoreRecord is only ~16 bytes instead of ~1040+ bytes.
This makes Vector operations on the records list dramatically cheaper
since memmove now shifts pointers instead of kilobyte-sized buffers.
To allow these to be reverted, we store mutation logs per object store
in the scope of a readwrite transaction to track the modifications that
were made by it. If a revert is needed, the log is played in reverse to
bring us back to the original state.
