RFR: 8254996: make jdk.net.UnixDomainPrincipal a record class [v3]

[Patrick Concannon]

> Hi,
> 
> Could someone please review my code for JDK-8254996: 'make jdk.net.UnixDomainPrincipal a record class'?
> 
> `jdk.net.UnixDomainPrincipal` is a simple immutable data class that requires boilerplate methods for access. However, these methods and fields are susceptible to trivial mistakes and add to the verbosity of the class. 
> This fix replaces the data class with a record class, a new type in JDK 16, making the code more concise and easier to maintain. This code is binary compatible with the original. For the generated API doc change, please refer to the specdiff attached to the CSR.
> 
> CSR : https://bugs.openjdk.java.net/browse/JDK-8257823
> 
> Kind regards,
> Patrick

Patrick Concannon 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 three additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into JDK-8254996
 - Merge remote-tracking branch 'origin/master' into JDK-8254996
 - 8254996: make jdk.net.UnixDomainPrincipal a record class

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1668/files
  - new: https://git.openjdk.java.net/jdk/pull/1668/files/2adf1455..b00569d7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1668&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1668&range=01-02

  Stats: 132 lines in 7 files changed: 125 ins; 1 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1668.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1668/head:pull/1668

PR: https://git.openjdk.java.net/jdk/pull/1668