math/big: use built-in clear to simplify code
Change-Id: I07c3a498ce1e462c3d1703d77e7d7824e9334651
GitHub-Last-Rev:
2ba8c4c705eaeb0772109ece7296978b62467eb3
GitHub-Pull-Request: golang/go#66312
Reviewed-on: https://go-review.googlesource.com/c/go/+/571636
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>