RFR: 8366478: BigDecimal roots [v32]

[fabioromano1]

> An implementation of `BigDecimal.nthRoot(int, MathContext)`.

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

  Simplified result's assertions for n < 0

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27148/files
  - new: https://git.openjdk.org/jdk/pull/27148/files/9ac75762..97502734

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27148&range=31
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27148&range=30-31

  Stats: 35 lines in 1 file changed: 7 ins; 14 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/27148.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27148/head:pull/27148

PR: https://git.openjdk.org/jdk/pull/27148