RFR: 8277489: Rewrite JAAS UnixLoginModule with FFM [v2]

[Weijun Wang]

> Rewrite the native calls with FFM.

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

  rewrite without jextract

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28931/files
  - new: https://git.openjdk.org/jdk/pull/28931/files/f3887714..8c0c7c0b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28931&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28931&range=00-01

  Stats: 1127 lines in 7 files changed: 94 ins; 1010 del; 23 mod
  Patch: https://git.openjdk.org/jdk/pull/28931.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28931/head:pull/28931

PR: https://git.openjdk.org/jdk/pull/28931