RFR: 8077587: BigInteger Roots [v39]

[fabioromano1]

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

fabioromano1 has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 84 commits:

 - Merge branch 'openjdk:master' into nth-root-branch
 - Revision changes
 - More accurate lower bound for doubles values tests
 - No need to ceiling the initial estimate if not shifted
 - Ensure an initial overestimate of the root
   
   Ensure an initial overestimate of the root, using Math.exp() and Math.log(), whose error is guaranteed to be less than 1 ulp.
 - Merge branch 'nth-root-branch' of https://github.com/fabioromano1/jdk into nth-root-branch
 - Added bug id
 - Refinement of javadoc for nth root
 - No need to check for root's shift overflow
 - Include one more possible correct bit in initial estimate
 - ... and 74 more: https://git.openjdk.org/jdk/compare/ad510fb2...ec5816dd

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

Changes: https://git.openjdk.org/jdk/pull/24898/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24898&range=38
  Stats: 408 lines in 3 files changed: 406 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