Revert "Merge pull request #7661 from ernie/build-join-records-on-unsaved-hmt"

This reverts commit ee439895759b38431ad025f3c234831f30dadcdb.

It would appear that #7661 had unintended consequences to the API. Until
we can sort those out, this should not be in 3.2.x, and wait for 4.0.0.
Merge pull request #8895 from ernie/revert-hmt-on-unsaved-in-3-2

Revert hm:t on unsaved collection for 3.2