RFR: 8354871: Replace stack map frame type magics with constants [v3]

[duke]

On Sat, 6 Sep 2025 13:48:53 GMT, Francesco Andreuzzi <duke at openjdk.org> wrote:

>> In this PR I introduce some constants in `StackMapGenerator`. No change in logic is expected.
>> 
>> Passes tests in `jdk/classfile`.
>
> Francesco Andreuzzi has updated the pull request incrementally with one additional commit since the last revision:
> 
>   inclusive

@fandreuz 
Your change (at version 0c6c04b7b8874d3b3bd53c4f9456fe01b151241d) is now ready to be sponsored by a Committer.

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PR Comment: https://git.openjdk.org/jdk/pull/27029#issuecomment-3262317395