Resume if not all test cases were executed due to early exit

[pdawyndt]

When multiple test cases are executed in a single run, and not all test cases are executed, we might make a distinction whether this is due to a time limit being exceeded or any other reason (e.g. submission exits unexpectedly). In the latter case, it would be better if we execute the remaining test cases in a new run.

Here's an example where students might otherwise see "Context not executed" for reasons they cannot explain.