[lworld] RFR: JDK-8251986: [lworld] implement Class::valueType and Class::referenceType in Java [v4]

[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:

  fix comment

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

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/152/files
  - new: https://git.openjdk.java.net/valhalla/pull/152/files/0e576ad3..1dcd5f3b

Webrevs:
 - full: https://webrevs.openjdk.java.net/valhalla/152/webrev.03
 - incr: https://webrevs.openjdk.java.net/valhalla/152/webrev.02-03

  Stats: 3 lines in 1 file changed: 2 ins; 0 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