RFR: 8367603: Optimize exact division in BigDecimal [v25]

[fabioromano1]

> A formula to lower the overestimate for the precision of an exact quotient, without introducing too expensive operations of division on numerator and denominator.

fabioromano1 has updated the pull request incrementally with two additional commits since the last revision:

 - Removed trailing whitespaces
 - Added further tests

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27271/files
  - new: https://git.openjdk.org/jdk/pull/27271/files/cf2a309e..aecc5536

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27271&range=24
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27271&range=23-24

  Stats: 48 lines in 1 file changed: 47 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27271.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27271/head:pull/27271

PR: https://git.openjdk.org/jdk/pull/27271