swiftlang/swift#39143 (Apache license)

Currently we use a simple rejection loop for generating int/long in a range

and other overloads. It may be that the Swift algorithm above is faster.

(Note that our existing algorithm is dropping high bits of the raw random result to minimize the rejections. If we can avoid doing that possibly it would improve the distribution?).

(I'm ignoring our legacy seeded impl which prefers reproducibility)