RFR: 8077587: BigInteger Roots [v12]

[fabioromano1]

> This PR implements nth root computation for BigIntegers using Newton method.

fabioromano1 has updated the pull request incrementally with two additional commits since the last revision:

 - Merge branch 'nth-root-branch' of https://github.com/fabioromano1/jdk into nth-root-branch
 - Compute remainder in the final loop to do less iterations

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24898/files
  - new: https://git.openjdk.org/jdk/pull/24898/files/3d8562f1..0cfb4f65

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=10-11

  Stats: 60 lines in 2 files changed: 17 ins; 13 del; 30 mod
  Patch: https://git.openjdk.org/jdk/pull/24898.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24898/head:pull/24898

PR: https://git.openjdk.org/jdk/pull/24898