crypto: use byteorder to simplify consumeUint32 and consumeUint64
A follow-up for the recent CL 585017.
Change-Id: I9faaff7fdf62fc931fc7f64dbe238de277280730
GitHub-Last-Rev:
468d60c3960751c1eec81c6ef1a57ab9e32f2eb8
GitHub-Pull-Request: golang/go#67425
Reviewed-on: https://go-review.googlesource.com/c/go/+/586035
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>