RFR: 8358624: ImmutableDescriptor violates equals/hashCode contract after deserialization [v2]

[Kevin Walls]

> Hashcode needs to be reset to -1 to force its recalculation on next call, after deserialization.
> 
> The change in the readResolve() method is the fix for this problem.  While here I added similar lines in other methods that may update fields (although these are noted as not supported, as they change a class supposedly "immutable").
> 
> Added a test.  There is a test for serialization for this class, but I found it clearer to add the test for this specific recently discovered issue in its own test file.

Kevin Walls has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains six additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into 8358624_ImmutableDescriptor_hashcode
 - spelling
 - Exception name
 - whitespace
 - whitespace
 - 8358624: ImmutableDescriptor violates equals/hashCode contract after deserialization

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25758/files
  - new: https://git.openjdk.org/jdk/pull/25758/files/a94b49ef..6f28e857

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25758&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25758&range=00-01

  Stats: 14540 lines in 274 files changed: 10342 ins; 3094 del; 1104 mod
  Patch: https://git.openjdk.org/jdk/pull/25758.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25758/head:pull/25758

PR: https://git.openjdk.org/jdk/pull/25758