RFR: 8077587: BigInteger Roots [v32]

[fabioromano1]

> This PR implements nth root computation for `BigInteger`s using Newton method and optimizes `BigInteger.pow(int)` method.

fabioromano1 has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 38 additional commits since the last revision:

 - Merge branch 'openjdk:master' into BigInteger-nth-root
 - Optimized nth root iteration loop
 - Systematization of special cases in BigInteger.pow(int)
 - Some optimizations
 - Optimized repeated squaring trick using cache for powers
 - Optimized BigInteger.pow(int) for single-word values
 - An optimization
 - Format code
 - Optimized computation of nth root's remainder
 - Delete useless folder
 - ... and 28 more: https://git.openjdk.org/jdk/compare/b8bb1cbf...f9bfd22c

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24690/files
  - new: https://git.openjdk.org/jdk/pull/24690/files/23914e8a..f9bfd22c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24690&range=31
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24690&range=30-31

  Stats: 35561 lines in 1017 files changed: 26806 ins; 6281 del; 2474 mod
  Patch: https://git.openjdk.org/jdk/pull/24690.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24690/head:pull/24690

PR: https://git.openjdk.org/jdk/pull/24690