all: use unsafe.{Slice, SliceData, String, StringData} to simplify code
Because most of these APIs are recently supported, we can only do some
advancement work as much as possible under the premise of compatibility.
For #54854.
Change-Id: Id15d11288bf23902570d54eaf2704a5264210b2e
Reviewed-on: https://go-review.googlesource.com/c/go/+/429115 Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: hopehook <hopehook@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>