RFR: 8346107: Generators: testing utility for random value generation [v2]

[Emanuel Peter]

> For verification testing, it is often critical to generate "interesting" values, to provoke overflows, NaN, etc. And to generate these values in the correct distribution to trigger certain optimizations.
> 
> I would like to start a collection of such generators, that can then be used in testing.
> 
> The goal is to grow this collection in the future, and add new types. For example `byte`, `char`, `short`, or even `Float16`.
> 
> This will be helpful for the Template framework [JDK-8344942](https://bugs.openjdk.org/browse/JDK-8344942), but also other tests.
> 
> Related PR, for value verification: https://github.com/openjdk/jdk/pull/22715

Emanuel Peter has updated the pull request incrementally with three additional commits since the last revision:

 - use Generators.Random, rm some imports
 - rm whitespace
 - Extra documentation, and review suggestions v1

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22716/files
  - new: https://git.openjdk.org/jdk/pull/22716/files/ed64bb91..219593a9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22716&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22716&range=00-01

  Stats: 299 lines in 21 files changed: 168 ins; 52 del; 79 mod
  Patch: https://git.openjdk.org/jdk/pull/22716.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22716/head:pull/22716

PR: https://git.openjdk.org/jdk/pull/22716