This change allows to drop brittle sizeof calls in favor of the
std::span::size method.
Other improvements include:
* Use of a namespace to mark test and bench data
* Use of the modern std::byte
* Drop of a no longer used std::vector copy and the bench/data module
By calling SaveBlockToDisk only when we actually want to save a new
block to disk. In the reindex case, we now call UpdateBlockInfo
directly from validation.
This commit doesn't change behavior.
