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

[Chen Liang]

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

Marked as reviewed by liach (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27029#pullrequestreview-3192855414