It is hard to tell where the `log_hook` log comes from, when we run test
parallelly. Add test name as field as debug purpose.
```
log_hook.go:47: time="2023-01-29T13:09:37.687070239+08:00" level=debug msg=fetch func=remotes.Fetch file="/home/fuwei/go/src/github.com/containerd/containerd/remotes/handlers.go:114" digest="sha256:ea362f368469f909a95f9a6e54ebe0121ce0a8e3c30583dd9c5fb35b14544dec" mediatype=application/vnd.docker.image.rootfs.diff.tar.gzip size=28566425 testcase=TestCRIImagePullTimeout/NoDataTransferred
```
REF: #8024
Signed-off-by: Wei Fu <fuweid89@gmail.com>
The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
