strconv: use slices.BinarySearch to simplify makeisprint.go
Change-Id: I9886a99f730b7616f6f8a5e6154e1beb7d3c79e6
GitHub-Last-Rev:
3f9dc7707377f79968e2dfcd206b83db21e60e60
GitHub-Pull-Request: golang/go#66242
Reviewed-on: https://go-review.googlesource.com/c/go/+/570535
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>