[dev.fuzz] internal/fuzz: add extra []byte mutators
Adds four []byte mutators which:
* insert a chunk of constant bytes
* overwirtes a chunk with constant bytes
* shuffle a range of bytes
* swaps two chunks
Also updates the 'set byte to random value' mutator to use XOR in
order to avoid a no-op.
Additionally updates the rng call which chooses the []byte mutators
so all the available mutators are used.
Change-Id: I0703518922952f4b1c81b19b196ee91c73b0d5f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/313270
Trust: Roland Shoemaker <roland@golang.org>
Trust: Katie Hockman <katie@golang.org>
Run-TryBot: Roland Shoemaker <roland@golang.org>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Katie Hockman <katie@golang.org>