uv3 deserialize compressed form 4 sofas not being indexed correctly

Traced a strange bug to the deserialization for form 4 compressed - getting a NPE. Root cause is the index info being deserialized is written with a conversion that changes the "address" of FSs to incrementing indexes (because they compress better). But the serialization code doesn't do this for Sofas. Mostly this doesn't matter by accident. But the special test case done in DocumentAnnotation test trips this bug.

Fix is in deserialization: after reading the sofa index number (which was written as v2 addresses, not converted to sequential) is to convert it to sequential so the rest of the code (which expects this) works. In v2, not an issue, but an improvement was made in v3 which broke this.