RFR: 8254275: [valhalla/jep390] Revise "value-based class" & apply to wrappers [v9]

[Dan Smith]

> Polishing the specification of "value-based class" to align with requirements of inline classes, allow classes (like Integer) with deprecated constructors, and clarify expectations for clients.
> 
> Full docs build: http://cr.openjdk.java.net/~dlsmith/8254275/8254275-20201013/api/index.html

Dan Smith has updated the pull request incrementally with one additional commit since the last revision:

  review feedback: toString, equals, hashCode in ValueBased.html

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Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/222/files
  - new: https://git.openjdk.java.net/valhalla/pull/222/files/a327a32d..4c21b225

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=222&range=08
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=222&range=07-08

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/222.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/222/head:pull/222

PR: https://git.openjdk.java.net/valhalla/pull/222