RFR: 8077587: BigInteger Roots [v19]

[Shaojin Wen]

On Sun, 20 Apr 2025 16:07:56 GMT, fabioromano1 <duke at openjdk.org> wrote:

>> This PR implements nth root computation for `BigInteger`s using Newton method and optimizes `BigInteger.pow(int)` method.
>> [Here is a proof of convergence of the recurrence used.](https://github.com/user-attachments/files/19785045/nth_root_newton_proof_integers.pdf)
>
> fabioromano1 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Code simplification

It is recommended not to format or rename unrelated code in this PR. You should make minimal changes to achieve the purpose of this PR.

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PR Comment: https://git.openjdk.org/jdk/pull/24690#issuecomment-2817450601