[lworld] RFR: 8371429: [lworld] Fix package name inference for ResourcePoolManager for preview mode [v2]

[David Beaumont]

> Switches package inference to handle preview resource paths.
> 
> Additionally:
> * Updates unit test to use JUnit.
> * Deletes unused code (both newly unused and previously unused).

David Beaumont has updated the pull request incrementally with one additional commit since the last revision:

  remove duplicate assert and update copyright

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1724/files
  - new: https://git.openjdk.org/valhalla/pull/1724/files/2cd62fc3..e6a4f64b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1724&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1724&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1724.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1724/head:pull/1724

PR: https://git.openjdk.org/valhalla/pull/1724