parse_and_run_program doesn't return a log when it errors

[Alex-Fischman]

I have a program with the following strucutre:

; ...
(extract var1)
(check (= var1 (...))))

I should be able to get the extracted expression whether the check succeeds or not. However, because parse_and_run_program returns a Result<Vec<String>, Error>, I can't. Instead, it should return something like (Vec<String>, Option<Error>), because not all errors invalidate the log.