RFR: 8357913: Add `@Stable` to BigInteger and BigDecimal [v3]

[Shaojin Wen]

> Some static final arrays of BigInteger and BigDecimal are stable and immutable. We should add `@Stable` to give the optimizer more information

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

  BigInteger::mag remove Stable

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25437/files
  - new: https://git.openjdk.org/jdk/pull/25437/files/11e31614..4e9be2c6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25437&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25437&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25437.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25437/head:pull/25437

PR: https://git.openjdk.org/jdk/pull/25437