[lworld] RFR: 8329795: [lworld] Remove the jdk internal ValhallaFeatures test api

[Mandy Chung]

On Fri, 5 Apr 2024 17:55:29 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

> The api point jdk.internal.misc.ValhallaFeatures has been replaced by `--enable-preview` and `jdk.internal.misc.PreviewFeatures` and can be removed. 
> 
> The supporting files and test are removed.

Marked as reviewed by mchung (Committer).

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

PR Review: https://git.openjdk.org/valhalla/pull/1071#pullrequestreview-1984007457