[jfx25u] RFR: 8371052: Update libFFI to 3.5.2

[Alexander Matveev]

Clean backport of JDK-8371052.

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Commit messages:
 - Backport 637cb63d9f3834699b99c408c6cee66a0ad4431f

Changes: https://git.openjdk.org/jfx25u/pull/36/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx25u&pr=36&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8371052
  Stats: 267 lines in 24 files changed: 184 ins; 12 del; 71 mod
  Patch: https://git.openjdk.org/jfx25u/pull/36.diff
  Fetch: git fetch https://git.openjdk.org/jfx25u.git pull/36/head:pull/36

PR: https://git.openjdk.org/jfx25u/pull/36