net: use strings.SplitSeq and bytes.SplitSeq
Replace `for _, s := range {strings, bytes}.Split(v, sep)` with
`for s := range {strings, bytes}.SplitSeq(v, sep)`, to simplify
the code and reduce some memory allocations.
Change-Id: Idead4de1e3928fc75cc5ba8caeff85542f1243d5
GitHub-Last-Rev:
5fb196a073e7583b23b1ebb446d6c067580ed63a
GitHub-Pull-Request: golang/go#71554
Reviewed-on: https://go-review.googlesource.com/c/go/+/646216
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>