internal/core/adt: add tests for 3770
Issue #3770
Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: I3fd591afc05f8661140cfd1fcc44ec79f2030199
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1211752
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>