RFR: Gradle cleanup [v2]

[Chen Liang]

On Thu, 3 Jul 2025 05:37:42 GMT, Clayton Walker <duke at openjdk.org> wrote:

>> I've been doing some development, and came across a few warnings during build.
>> 
>> These are, [Project::task](https://docs.gradle.org/current/javadoc/org/gradle/api/Project.html#task(java.lang.String)) is now deprecated, avoiding Project::mkdir, project::delete and Project::getProjectDir as they cannot work under configuration-cache.
>
> Clayton Walker has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:
> 
>   Fix running with configuration-cache enabled

Haven't used gradle in a while so don't know about the latest deprecations, but these changes are existing gradle styles and make sense.

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Marked as reviewed by liach (no project role).

PR Review: https://git.openjdk.org/jextract/pull/283#pullrequestreview-2983629813