RFR: 8358890: VM option -XX:AllowRedefinitionToAddDeleteMethods should be obsoleted then expired [v4]

[Serguei Spitsyn]

> The VM option -XX:AllowRedefinitionToAddDeleteMethods was added in JDK 13 as a temporary backward compatibility flag under JDK-8192936 and was immediately marked as Deprecate. The fix is to obsolete this option in JDK 26 and expire in JDK 27.
> 
> TBD: Need to submit a related CSR.
> 
> There are two concerns which may require some negotiation with the Runtime (@coleenp @dcubed-ojdk @dholmes-ora) and SQE (@lmesnik) teams:
>  - Class redefinition/retransformation can impact lambda expressions which are supported with private methods
>  - Many tests depend on this VM option and are being removed. I'm not sure if it is okay to completely remove those e may want another way to handle this (e.g. problem-listing the impacted tests for now).
>  
> Testing:
>  - mach5 tiers 1-6 are good
>  - may need to run mach5 tiers > 6

Serguei Spitsyn has updated the pull request incrementally with one additional commit since the last revision:

  review: replace RESERVED flag with UNUSED

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26232/files
  - new: https://git.openjdk.org/jdk/pull/26232/files/833c6169..fc5630c1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26232&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26232&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26232.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26232/head:pull/26232

PR: https://git.openjdk.org/jdk/pull/26232