servo: Merge #11251 - Added test that files exist to etc/ci/check_no_unwrap.sh (from asajeffrey:check-no-unwrap-check-for-files); r=aneeshusa

Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data:
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy --faster` does not report any errors
- [X] No github issue.

Either:
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because this PR updates test code.

Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process.

Source-Repo: https://github.com/servo/servo
Source-Revision: 2d5dc8fa6db4d714c2018d78f502b3298a32cfaf

servo/etc/ci/check_no_unwrap.sh

@@ -13,4 +13,8 @@ FILES=("components/compositing/compositor.rs"
        "components/compositing/pipeline.rs"
        "components/constellation/constellation.rs")
 
-! grep -n "unwrap(\|panic!(" "${FILES[@]}"
+# make sure the files exist
+ls -1 "${FILES[@]}"
+
+# make sure the files do not contain "unwrap" or "panic!"
+! grep --line-number --with-filename "unwrap(\|panic!(" "${FILES[@]}"