Summary:
This field is never set, but it was being tested and used to decide
whether to resolve an object or not.  This caused non-deterministic
crashes when using the RTS linker (see #12230).

I suspect this is not the correct fix, but putting it up so that Phyx
can tell us what the right fix should be.

Test Plan: validate

Reviewers: austin, Phyx, bgamari, erikd

Subscribers: erikd, thomie, ezyang

Differential Revision: https://phabricator.haskell.org/D2371

GHC Trac Issues: #12230