Actually recognize ASan error messages

[saethlin]

crater-at-home/src/diagnose.rs

Lines 70 to 79 in eaaea3d

	if line.contains("requested allocation size") {
	causes.push(Cause {
	kind: "requested allocation size exceeds maximum supported size".to_string(),
	source_crate: None,
	});
	} else if let Some(kind) = line.split_whitespace().nth(2) {
	causes.push(Cause {
	kind: kind.to_string(),
	source_crate: None,
	});

ASan diagnosis only special-cases the too-large allocations. So we end up with some goofy diagnoses like UB: SEGV which should indicate clearly that this is a null pointer deref, and UB: attempting which is just the first word of "attempting double free".