fix: Return non-zero exit codes from analyzer-binary

Previously we would ignore non-zero exits and proceed with VET and TC. We should not do that as it's (A) inefficient and results in an incorrect exit code as start.sh returns exit 0 in all cases.

There is an additional and more minor bug I pushed up independently with !5 (merged), this MR is a dependency for that one.

Relates to gitlab-org/gitlab#342434 (closed)