[lworld] RFR: 8372038: [lworld] Update ExplodedImage to use preview mode correctly [v2]

[David Beaumont]

On Wed, 26 Nov 2025 13:07:41 GMT, David Beaumont <duke at openjdk.org> wrote:

>> Adds preview mode support for ExplodedImage.
>> 
>> Adds tests so both ExplodedImage and ImageReader implementations of SystemImage are tested with exactly the same test data and assertions.
>
> David Beaumont has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fixing duplicate elements

test/jdk/jdk/internal/jrtfs/SystemImageTest.java line 348:

> 346:         ImageReader.Node dir = assertDir(image, name);
> 347:         // Use a list (not a set) to avoid hiding duplicate entries.
> 348:         List<String> localChildNames = dir.getChildNames()

This test was previously using a set, and accidentally folding duplicates, meaning it didn't spot the issue of duplicate child nodes.

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1743#discussion_r2564944991