test: Redact conditional compile-fail warning

I got a CI failure because the following line showed up:
```
[WARNING] build failed, waiting for other jobs to finish...
```
I'm assumin this is a race condition in the test for whether the
successful target completed before the error or not.

Before snapbox, we used a `contains` check which didn't have this
problem.  I'm replacing this with a `...` multi-line (0+) glob.

Author: epage

tests/testsuite/artifact_dep.rs

@@ -447,6 +447,7 @@ error[E0425]: cannot find function `f2` in crate `d2`
 
 For more information about this error, try `rustc --explain E0425`.
 [ERROR] could not compile `d1` (bin "d1") due to 1 previous error
+...
 
 "#]])
         .run();