ResourcePoolManager attempts to infer package names for jimage directories from their path, but this fails when preview resource exist.

To satisfy the package consistency requirements in the module system between the module definition and the module contents, a preview class/resource should be inferred to have the equivalent non-preview package.

This only makes a difference if preview only packages exist, where the preview only-package would need to be listed in the module definition even when not running in preview mode since there's no ability to switch module definitions based on preview mode (and failing to have a preview-only package when in preview mode would cause issues).