Added jtreg-buffer testsuite

[judovana]

based on:
#5195
#5167

[judovana]

s390x https://ci.adoptium.net/view/Test_grinder/job/Grinder/9927
aarch64 https://ci.adoptium.net/view/Test_grinder/job/Grinder/9928/

[karianna]

Need to understand why :-)

[judovana]

Need to understand why :-)

Yah. That it honest question, and not easy one indeed! Various reasons, from dummy ones like: Original author quit, original author forget, original author was lazy or simply not brave enough to push it. And later, no one had time to take it over. Not exactly an good excuse, but is covering about half of the tests. I would silently nod in agreeing to anybody refusing to accept this test set for this reason. But I tried to do quite a few in past, and burned out on it. Other reasons are weird corner cases, which do not run everywhere. Most of them are currenly labeled as var.rh.jdk although better would be rhel.and.fedora. Others may get this label once I see them to fail on some Adoptium combination I had not yet tried. Some have security manager. And as that is going to be dropped, but not dropped, or at least not soon, usptream is not accepting new tests with SM. Soem of them were upstreamed in form, that the intersection of covered code was not identical, or illegible for backport. So we decided to keep also orignal version (see speed)
Main of all is speed. upstreaming test is sometimes lengthy (and triple it when you porting it down to the JDK where you need it most), and if one need a testcase asap... That is actually why this repo was ever created. Howerv... from there, is it super easy to slip... goto "dummy ones"; And thats why it is not empty, but actually grown a bit.

[judovana]

I had recalled, that I was tracking the upstreaming. Its part of the repo, you can see it via githubhack: https://rawcdn.githack.com/rh-openjdk/jtreg-buffer/581161a13dd731f9eac1f89e5164884a77465bca/dupes.html

the removed are the tests which were upstreamed