testing/slogtest: test nested groups in empty record
Updates #62280
Change-Id: I1c80cb18bb174b47ff156974f72c37baf6b73635
GitHub-Last-Rev:
d98b6cd57eb028af8513f583cbef3ce46505b590
GitHub-Pull-Request: golang/go#65597
Reviewed-on: https://go-review.googlesource.com/c/go/+/562635
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Sean Liao <sean@liao.dev>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Sean Liao <sean@liao.dev>