RFR: 8372258: Improve TypeVariable support [v2]

[Chen Liang]

On Mon, 24 Nov 2025 10:03:16 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> The `TypeVariableImpl::getGenericDeclaration` method should return copies of generic declarations where appropriate.
>
> Per Minborg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Change docs for TypeVaiable

This version looks better. Meanwhile you can update the copyright header of TypeVariable.java.

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Marked as reviewed by liach (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28429#pullrequestreview-3503281421