test: skip SEA tests when SEA generation fails
In the SEA tests, if any of these steps fail:
- Copy the executable
- Inject the SEA blob
- Signing the SEA
We skip the test because the error likely comes from the system or postject and is not something the Node.js core can fix. We only leave an exception for a basic test that test injecting empty files as SEA to ensure the workflow is working (but we still skip if copying fails or signing fails on Windows).