[lworld] RFR: 8328543: [lworld] Library and test updates to use --enable-preview instead of ValhallaFeatures [v5]

[Roger Riggs]

> Update AccessFlag and tests to JEP 401 and use of --enable-preview instead of ValhallaFeatures.
> Minor formatting change to java.lang.Character to allow it to be a value class with --enable-preview.
> (The class file format version numbers will need to be updated when re-synching with the mainline).

Roger Riggs has updated the pull request incrementally with two additional commits since the last revision:

 - remove extraneous text
 - Update src/java.base/share/classes/java/lang/reflect/AccessFlag.java
   
   Co-authored-by: Mandy Chung <mandy.chung at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1060/files
  - new: https://git.openjdk.org/valhalla/pull/1060/files/bd5886a1..cc7ac497

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1060&range=04
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1060&range=03-04

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1060.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1060/head:pull/1060

PR: https://git.openjdk.org/valhalla/pull/1060