RFR: 8346106: Verify.checkEQ: testing utility for recursive value verification [v3]

[Emanuel Peter]

> In testing, we often generate "golden" values, and then compare the results with it. This requires comparison loops etc in every test. I would like to create a dedicated facility for this, to simplify testing in the future. This is also preparation for [JDK-8344942](https://bugs.openjdk.org/browse/JDK-8344942), the Template framework.
> 
> I have written code like this in various tests before, see:
> `test/hotspot/jtreg/compiler/loopopts/superword/TestAlignVectorFuzzer.java`
> `./test/hotspot/jtreg/compiler/loopopts/superword/TestMemorySegment.java`
> `test/hotspot/jtreg/compiler/loopopts/superword/TestIndependentPacksWithCyclicDependency.java`.
> 
> It is now time to make a proper facility, so I can save time when writing tests in the future.
> 
> A related PR, for value generation: https://github.com/openjdk/jdk/pull/22716

Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:

  improve documentation

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22715/files
  - new: https://git.openjdk.org/jdk/pull/22715/files/7a65b747..bf1377f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22715&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22715&range=01-02

  Stats: 21 lines in 2 files changed: 13 ins; 4 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/22715.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22715/head:pull/22715

PR: https://git.openjdk.org/jdk/pull/22715