compress/flate: use built-in clear to simplify the code
The new bootstrap toolchain allows us to use the built-in clear.
Updates #64751
Change-Id: Ic363e1059f34c46eaa4267c0b40a4ed8d5b3961b
GitHub-Last-Rev:
46ca735bfcd99a9874d7904a705970ed0cadf61c
GitHub-Pull-Request: golang/go#69253
Reviewed-on: https://go-review.googlesource.com/c/go/+/610516
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>