cue: add another test for a disjunction bug fixed in evalv3

The old evaluator incorrectly errors, but the new one doesn't.

While here, namespace the fields of the recently added issue1417.cue,
which I forgot to do, and makes the file consistent with the others.

Closes #3149.

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>
Change-Id: I1cdf4af8aa52c0ca8dd1ff82c42b0b5c25bb4e20
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1194855
Reviewed-by: Marcel van Lohuizen <mpvl@gmail.com>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>