internal/core/adt: add tests for Issue 3929
This got fixed somewhere along the way.
Fixes #3929
Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: I2b7486445208aabc4e462ae66291c2134d5c1bff
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1217128
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>