internal/fuzz: minimize bytes to be human readable

internal/fuzz: minimize bytes to be human readable

Try to replace every byte with one of the following printable
characters: "012789ABCXYZabcxyz !\"#$%&'()*+,.".

Fixes #48129

Change-Id: Ie58f6bbc3431d50d9f0a3f608ba63e854ac6ce79
Reviewed-on: https://go-review.googlesource.com/c/go/+/352614
Reviewed-by: Katie Hockman <katie@golang.org>
Reviewed-by: Amelia Downs <adowns@vmware.com>
Trust: Katie Hockman <katie@golang.org>
Trust: Julie Qiu <julie@golang.org>
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>