go/build/constraint: delete, replace stringsCut calls with strings.Cut
Currently, the Go bootstrap toolchain is bumped to 1.20.
Change-Id: I6467768c0640a8e9aadbfea79cfdfb14b4b80679
GitHub-Last-Rev:
7cf2d54a4865b4c6c15af374a6c0fbdbcce8c3b6
GitHub-Pull-Request: golang/go#63174
Reviewed-on: https://go-review.googlesource.com/c/go/+/530676
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: qiulaidongfeng <2645477756@qq.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>