Use resume_unwind instead of panic!() for nicer errors

Author: bjorn3

src/runtest.rs

@@ -2629,7 +2629,9 @@ impl ProcRes {
             \n",
                self.status, self.cmdline, self.stdout,
                self.stderr);
-        panic!();
+        // Use resume_unwind instead of panic!() to prevent a panic message + backtrace from
+        // compiletest, which is unnecessary noise.
+        std::panic::resume_unwind(Box::new(()));
     }
 }