RFR: 8339260: Move rarely used constants out of ClassFile [v9]

[Adam Sotona]

On Tue, 24 Sep 2024 17:23:41 GMT, Chen Liang <liach at openjdk.org> wrote:

>> Many constants are cluttered in `ClassFile`. However, only a few of them are ever used by regular users, most notably `ACC_` flags and `JAVA_X_VERSION` constants. All other constants are specific and should live in more local locations, such as getters that return these constants.
>> 
>> This simplification of `ClassFile` constants improves user onramp to the Class-File API.
>> 
>> Notably, before, if `ClassFile` is static imported, `Opcode` enums must be qualified due to name clashes; this relocation allows `Opcode` enums to be static imported with `ACC_` flags, improving class file writing user experience.
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   AbstractPoolEntry is broken too

Marked as reviewed by asotona (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/20773#pullrequestreview-2327211669