RFR: 8341470: BigDecimal.stripTrailingZeros() optimization [v47]

[fabioromano1]

> An optimized algorithm for `BigDecimal.stripTrailingZeros()` that uses repeated squares trick.

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

  Refining the loop invariant for more clear proof

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21323/files
  - new: https://git.openjdk.org/jdk/pull/21323/files/e91ebe83..929d0abe

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21323&range=46
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21323&range=45-46

  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/21323.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21323/head:pull/21323

PR: https://git.openjdk.org/jdk/pull/21323