interactive autograder: better failure checks (#2165)
interactive autograder robustness: safer error checks (#2165)
Revert "interactive autograder robustness: safer error checks (#2165)"

This reverts commit 865ac82b041d5df18628a294a0392a75de6079ab.
interactive autograder: test with score == 0 (#2165)
Merge pull request #2179 from Stanford-Online/sef-2165-better-interactive-autograder-check

interactive autograder: better failure checks (#2165)