Sylvain Henry authored Jun 16, 2023 and Marge Bot committed Jun 26, 2023

- thread knowledge about levity into PrimRep instead of panicking
- JS: remove assumption that unlifted heap objects are rts objects (TVar#, etc.)

Doing this also fixes #22291 (test added).

There is a small performance hit (~1% more allocations).

Metric Increase:
    T18698a
    T18698b