[lworld] RFR: JDK-8251986: [lworld] implement Class::valueType and Class::referenceType in Java [v5]

[Mandy Chung]

> Now that javac generates the reference projection class as a sealed type,
> this patch reimplements  `Class::valueType` and `Class::referenceType` in Java.
> VM no longer has any knowledge of the value projection type and reference projection type.
> 
> This patch includes a temporary workaround to disable the preview feature check
> for sealed types because inline types are not (yet) a preview feature in valhalla repo.
> This workaround should be removed when it's time to make inline class a preview feature.

Mandy Chung has updated the pull request incrementally with one additional commit since the last revision:

  improve getProjectionTypes per Roger's suggestion

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

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/152/files
  - new: https://git.openjdk.java.net/valhalla/pull/152/files/1dcd5f3b..de9d8505

Webrevs:
 - full: https://webrevs.openjdk.java.net/valhalla/152/webrev.04
 - incr: https://webrevs.openjdk.java.net/valhalla/152/webrev.03-04

  Stats: 40 lines in 1 file changed: 18 ins; 21 del; 1 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/152.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/152/head:pull/152

PR: https://git.openjdk.java.net/valhalla/pull/152