reflect: allow Value.Bytes on addressable byte arrays

Modify Value.Bytes to be callable addressable byte arrays.
While related, the behavior of Value.SetBytes was not modified.

Fixes #47066

Change-Id: Ic3ba4432353b8da5f33b3188e20034a33b2f6ee8
Reviewed-on: https://go-review.googlesource.com/c/go/+/357331


Trust: Joseph Tsai <joetsai@digital-static.net>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Joseph Tsai <joetsai@digital-static.net>
TryBot-Result: Gopher Robot <gobot@golang.org>