internal/core/adt: decrement counter for defunct tasks
Not decrementing them can cause counter errors.
Signed-off-by: Marcel van Lohuizen <mpvl@gmail.com>
Change-Id: I2a0922737e7e4b3f40973aa1b6e918ae3dfc4fc9
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1199753
Reviewed-by: Matthew Sackman <matthew@cue.works>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>