RFR: 8365262: [IR-Framework] Add simple way to add cross-product of flags [v6]

[Emanuel Peter]

On Fri, 22 Aug 2025 09:36:45 GMT, Manuel Hässig <mhaessig at openjdk.org> wrote:

>> This PR adds the `TestFramework::addCrossProductScenarios` method to enable more ergonomic testing of the combination of all flag combinations. To illustrate its use, I also converted one test to use the new cross product functionality.
>> 
>> Testing:
>>  - [x] Github Actions
>>  - [x] tier1,tier2 plus some internal testing on Oracle supported platforms
>
> Manuel Hässig has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Improvements prompted by Emanuel

Changes requested by epeter (Reviewer).

test/hotspot/jtreg/compiler/lib/ir_framework/TestFramework.java line 387:

> 385:                         })
> 386:                     ),
> 387:                 (a, b) -> Stream.concat(a, b));

Wow, that's dense. Maybe a little comment could help here.

test/hotspot/jtreg/testlibrary_tests/ir_framework/tests/TestScenariosCrossProduct.java line 53:

> 51:             TestFramework t = new TestFramework();
> 52:             t.addCrossProductScenarios(null);
> 53:             Asserts.fail("Should not have thrown exception");

Should or should not have thrown?

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PR Review: https://git.openjdk.org/jdk/pull/26762#pullrequestreview-3144643027
PR Review Comment: https://git.openjdk.org/jdk/pull/26762#discussion_r2293833619
PR Review Comment: https://git.openjdk.org/jdk/pull/26762#discussion_r2293836677