crypto/subtle: use min builtin function in XORBytes
Change-Id: Ibf57dbaaa54486823e0769714dec2e22d6c5ea9e
GitHub-Last-Rev:
31421d066833f721f3fa261ac9dc49724fffb5f8
GitHub-Pull-Request: golang/go#65748
Reviewed-on: https://go-review.googlesource.com/c/go/+/564577
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>