RFR: 8077587: BigInteger Roots [v43]

[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:

  Update BigIntegerTest.java
  
  Adjust pow-nthRoot roundtrip tests to handle negative base with even exponent.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24898/files
  - new: https://git.openjdk.org/jdk/pull/24898/files/1dfa232f..c9cb4ec1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=42
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=41-42

  Stats: 7 lines in 1 file changed: 5 ins; 0 del; 2 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