RFR: 8329178: Clean up jdk.accessibility native compilation [v2]

[Magnus Ihse Bursie]

> This is a follow-up on JDK-8328680, making the same kind of cleanup to jdk.accessibility. The code here needed more work than for the other modules, so I wanted have it in a separate PR to get a more thorough review.

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Fix incorrect indentation

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Changes:
  - all: https://git.openjdk.org/jdk/pull/18510/files
  - new: https://git.openjdk.org/jdk/pull/18510/files/077baf60..a52d63cd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18510&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18510&range=00-01

  Stats: 26 lines in 1 file changed: 0 ins; 0 del; 26 mod
  Patch: https://git.openjdk.org/jdk/pull/18510.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18510/head:pull/18510

PR: https://git.openjdk.org/jdk/pull/18510