RFR: 8246774: implement Record Classes as a standard feature in Java [v12]

[Vicente Romero]

> 8246774: implement Record Classes as a standard feature in Java

Vicente Romero has updated the pull request with a new target base due to a merge or a rebase. The pull request now
contains 10 commits:

 - Merge branch 'master' into JDK-8246774
 - Merge branch 'master' into JDK-8246774
 - removing unused jcod file
 - remove unnecessary jtreg tags from tests, remove othervm etc when applicable
 - adding missing changes to some tests
 - modifiying @since from 14 to 16
 - Remove preview args from ObjectMethodsTest
 - Remove preview args from record serialization tests
 - removing the javax.lang.model related code to be moved to a separate bug
 - 8246774: Record Classes (final) implementation
   
   Co-authored-by: Vicente Romero <vicente.romero at oracle.com>
   Co-authored-by: Harold Seigel <harold.seigel at oracle.com>
   Co-authored-by: Jonathan Gibbons <jonathan.gibbons at oracle.com>
   Co-authored-by: Brian Goetz <brian.goetz at oracle.com>
   Co-authored-by: Maurizio Cimadamore <maurizio.cimadamore at oracle.com>
   Co-authored-by: Joe Darcy <joe.darcy at oracle.com>
   Co-authored-by: Chris Hegarty <chris.hegarty at oracle.com>
   Co-authored-by: Jan Lahoda <jan.lahoda at oracle.com>

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

Changes: https://git.openjdk.java.net/jdk/pull/290/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=290&range=11
  Stats: 856 lines in 109 files changed: 72 ins; 562 del; 222 mod
  Patch: https://git.openjdk.java.net/jdk/pull/290.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/290/head:pull/290

PR: https://git.openjdk.java.net/jdk/pull/290