The previous usage of `reduce` was basically implementing the `every`
A small difference is that the new implementation will stop checking
as soon as one element have returned false, which will reduce
the number of unnecessary checks.
* Prepend underscores to private modules
* Remove collectUint8Arrays() It would be a misuse of Deno.iter()'s result.
* Move std/_util/async.ts to std/async
* Move std/util/sha*.ts to std/hash