[lworld] RFR: 8346307: [lworld] Clarify identity vs value in Class, Objects, and document limitations of value objects [v8]

[Roger Riggs]

> Add APINote  and javadoc for IdentityException where it will be useful to know that identity or value objects are treated differently. 
> Simplified WeakHashMap javadoc updates for IdentityException. 
> Added note to System.identityHashCode to include value objects.
> Added to class javadoc for IdentityHashMap for value objects.

Roger Riggs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 12 commits:

 - Merge branch 'lworld' into 8346307-throws-identityexception
 - Merge branch 'lworld' into 8346307-throws-identityexception
 - Merge
 - Merge branch 'lworld' into 8346307-throws-identityexception
 - Merge branch 'lworld' into 8346307-throws-identityexception
 - Merge branch 'lworld' into 8346307-throws-identityexception
 - Merge
 - Expand javadoc reference to Reference
 - Merge remote-tracking branch 'refs/remotes/origin/8346307-throws-identityexception' into 8346307-throws-identityexception
 - Merge branch 'openjdk:lworld' into 8346307-throws-identityexception
 - ... and 2 more: https://git.openjdk.org/valhalla/compare/be146831...b6cd55b5

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

Changes: https://git.openjdk.org/valhalla/pull/1327/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1327&range=07
  Stats: 250 lines in 11 files changed: 193 ins; 14 del; 43 mod
  Patch: https://git.openjdk.org/valhalla/pull/1327.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1327/head:pull/1327

PR: https://git.openjdk.org/valhalla/pull/1327