RFR: 7903813: Tag enablePreview with false should take precedence [v4]

[Jonathan Gibbons]

On Mon, 9 Sep 2024 22:11:50 GMT, Christian Stein <cstein at openjdk.org> wrote:

>> Please review this change to let tests with `@enablePreview false` take precedence over libraries that require preview features being enabled.
>> 
>> Note that the [PreviewHiddenClass](https://github.com/openjdk/jdk/blob/f6d7e30b84fedbf42077526610ba7a5bcfaece4c/test/jdk/java/lang/invoke/defineHiddenClass/PreviewHiddenClass.java#L34-L35) test should receive an explicit `enablePreview=false` tag line (in addition to the comment).
>
> Christian Stein has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update BuildAction.java

OK. I probably would not have written the code that way, and might have done more to  emphasize the three-valued nature (unset, `true`, `false`) of `enablePreview` in the `TestDescription`.  I did have to go (re)read the code for `RegressionTestFinder` to see how/where that an empty string for `@enablePreview` was handled.  But part of that is on me, I guess, for the original code in this area.

-------------

Marked as reviewed by jjg (Lead).

PR Review: https://git.openjdk.org/jtreg/pull/225#pullrequestreview-2291045592