RFR: 8326227: Rounding error that may distort computeNextGaussian results [v4]

[Chris Hennick]

> This provides a slightly more accurate bounding limit for `computeNextExponentialSoftCapped` when calling it from `computeNextGaussian`. This could cause the `while (computeNextExponentialSoftCapped(rng, limit) < limit)` check in `computeNextGaussian` on line 1402 to always be true, making the `nextGaussian` runtime unbounded in the worst case; but more likely, it would give a result that was truncated too close to zero.
> 
> This change is being tested prior to submission to OpenJDK by https://github.com/openjdk/jdk/pull/17703/commits/b8be051cbf40a6a05fafc6a2c76942e9e0b11fdf.

Chris Hennick has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:

 - Merge branch 'openjdk:master' into patch-2
 - Bug fix: add-exports was for wrong package
 - Tweak boundary cases and add unit test
 - Bug fix: Math is in java.lang, not java.util
 - Fix a possible rounding error in RandomSupport::computeNextExponential
   
   This provides a slightly more accurate bounding limit for computeNextExponentialSoftCapped when the computed bound is greater than `(1.0p53 - 1.0) * DoubleZigguratTables.exponentialX0`.

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Changes: https://git.openjdk.org/jdk/pull/17703/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17703&range=03
  Stats: 41 lines in 2 files changed: 36 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/17703.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17703/head:pull/17703

PR: https://git.openjdk.org/jdk/pull/17703