[jfx21u] RFR: 8307536: FileAlreadyExistsException from NativeLibLoader when running concurrent applications with empty cache

[Jose Pereda]

Clean backport of 8307536: FileAlreadyExistsException from NativeLibLoader when running concurrent applications with empty cache

Reviewed-by: kcr, angorya, jvos

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Commit messages:
 - 8307536: FileAlreadyExistsException from NativeLibLoader when running concurrent applications with empty cache

Changes: https://git.openjdk.org/jfx21u/pull/26/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx21u&pr=26&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307536
  Stats: 20 lines in 1 file changed: 18 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jfx21u/pull/26.diff
  Fetch: git fetch https://git.openjdk.org/jfx21u.git pull/26/head:pull/26

PR: https://git.openjdk.org/jfx21u/pull/26