RFR: 8349923: Refactor StackMapTable constructor and StackMapReader [v2]

[Chen Liang]

On Fri, 14 Feb 2025 20:13:48 GMT, Matias Saavedra Silva <matsaave at openjdk.org> wrote:

>> This patch refactors the `StackMapReader` to clean up the `StackMapTable` constructor. The `StackMapReader` class is extended to hold more fields used for verification purposes and allows for a simpler StackMapTable constructor. Additionally, in preparation for further changes to verification, the `_frame_count` may not be equal to the value reported by the classfile. Verified with tier 1-5 tests
>
> Matias Saavedra Silva has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Coleen comments

> the `_frame_count` may not be equal to the value reported by the classfile

Context for other reviewers: This may happen with the new StackMapTable entries introduced by Value Objects JEP. https://cr.openjdk.org/~dlsmith/jep401/jep401-20241108/specs/value-objects-jvms.html#jvms-4.7.4

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PR Comment: https://git.openjdk.org/jdk/pull/23645#issuecomment-2661478846