runtime: use built-in clear to simplify code
Change-Id: Icb6d9ca996b4119d8636d9f7f6a56e510d74d059
GitHub-Last-Rev:
08178e8ff798f4a51860573788c9347a0fb6bc40
GitHub-Pull-Request: golang/go#66188
Reviewed-on: https://go-review.googlesource.com/c/go/+/569979
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: qiulaidongfeng <2645477756@qq.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>