Dumping traces for iree-samples targets is not supported

[hanhanW]

Coming from https://github.com/google/iree/issues/8712

I found that the traces are not generated when running the test target. It's really inconvenient when debugging the issue. I have a commit which dumps inputs myself. We should generalize it to testing module, and dump all the artifacts to a directory.

Example commit: https://github.com/google/iree-samples/commit/d9ff43840c71f7e760386dccfcf720c4f545b810