XORBytes was added to package crypto/subtle in Go 1.20, and it's faster
than our bitutil.XORBytes. There is only one use of this function
across go-ethereum so we can simply deprecate the custom implementation.
---------
Co-authored-by: Felix Lange <fjl@twurst.com>
Gollvm has very aggressive dead code elimination that completely
removes one of these two benchmarks. To prevent this, use the
result of the benchmark (a boolean), and to be "fair", make the
transformation to both benchmarks.
To be reliably assured of not removing the code, "use" means
assigning to an exported global. Non-exported globals and
//go:noinline functions are possibly subject to this optimization.
