hash: use more internal/byteorder functions to simplify the code
A follow-up for the CL 585015.
Change-Id: I412f33f1d75abe1446cb3fd742d44d3cb4350380
GitHub-Last-Rev:
554ace757cc75389e7a3c441d3a60cfa85c815a5
GitHub-Pull-Request: golang/go#67476
Reviewed-on: https://go-review.googlesource.com/c/go/+/586240
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Commit-Queue: Ian Lance Taylor <iant@google.com>