RFR: 8343881: java.lang.classfile.Attribute attributeName() method should return Utf8Entry [v2]

[Adam Sotona]

> Class-File API usually expose names in a form of `java.lang.classfile.constantpool.Utf8Entry`. Unfortunately `java.lang.classfile.Attribute::attributeName` method was omitted during the API review and it returns inflated `String` value of the name.
> 
> This patch changes return type of `java.lang.classfile.Attribute::attributeName` from `String` to `java.lang.classfile.constantpool.Utf8Entry`.
> 
> Please review.
> 
> Thanks,
> Adam

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  fixed tests

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22107/files
  - new: https://git.openjdk.org/jdk/pull/22107/files/dbf27666..6fb11386

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22107&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22107&range=00-01

  Stats: 18 lines in 10 files changed: 0 ins; 0 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/22107.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22107/head:pull/22107

PR: https://git.openjdk.org/jdk/pull/22107