RFR: 8357821: Revert incorrectly named JavaLangAccess::unchecked* methods [v2]

[Volkan Yazici]

> Reverts certain [JDK-8353197](https://bugs.openjdk.org/browse/JDK-8353197) (which implements JavaDoc improvement and precautionary naming for certain unsafe methods in `jdk.internal.access.JavaLangAccess`) changes that are found to be incorrect. See the JBS issue for details on the followed evaluation process.

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

  Add `@implSpec`

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/25545/files
  - new: https://git.openjdk.org/jdk/pull/25545/files/bbf42347..1e135598

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25545&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25545&range=00-01

  Stats: 6 lines in 1 file changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25545.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25545/head:pull/25545

PR: https://git.openjdk.org/jdk/pull/25545