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

[Benoît Maillard]

On Wed, 13 Aug 2025 14:38:01 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

Looks good to me, I only have one minor suggestion.

test/hotspot/jtreg/compiler/lib/ir_framework/TestFramework.java line 368:

> 366:                 .flatMap(setElement -> crossProductHelper(idx + 1, sets)
> 367:                         .map(set -> {
> 368:                             Set<String> newSet = new HashSet(set);

Suggestion:

                            Set<String> newSet = new HashSet<>(set);


You should use the diamond operator here to use the generic type instead of the raw `HashSet` type

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PR Review: https://git.openjdk.org/jdk/pull/26762#pullrequestreview-3127232286
PR Review Comment: https://git.openjdk.org/jdk/pull/26762#discussion_r2281603073