cmd/trace: pkg import only once
Change-Id: Iaaf2e9dbcffb4b1944817b0a4aaecd3554ebfec1
GitHub-Last-Rev:
f4ec85a05e54c2f403cabc4c6458cd2f396e183d
GitHub-Pull-Request: golang/go#67280
Reviewed-on: https://go-review.googlesource.com/c/go/+/584695
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>