RFR: 8077587: BigInteger Roots [v40]

[fabioromano1]

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

fabioromano1 has updated the pull request incrementally with one additional commit since the last revision:

  Ensure an initial overestimate of the root
  
  Ensure an initial overestimate of the root by doing 1st iteration outside the loop.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24898/files
  - new: https://git.openjdk.org/jdk/pull/24898/files/ec5816dd..6e10645f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=39
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=38-39

  Stats: 22 lines in 1 file changed: 14 ins; 3 del; 5 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