RFR: 8296535: Unnecessary Vector usage in AquaFileSystemModel.FilesLoader

[Andrey Turbanov]

`acceptsList` is created, filled and used only _locally_ in the method `com.apple.laf.AquaFileSystemModel.FilesLoader#run`.
So we can avoid usage of legacy synchronized `Vector` here and use `ArrayList` instead.

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Commit messages:
 - [PATCH] Unnecessary Vector usage in AquaFileSystemModel
 - [PATCH] Unnecessary Vector usage in AquaFileSystemModel

Changes: https://git.openjdk.org/jdk/pull/20962/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20962&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296535
  Stats: 15 lines in 1 file changed: 0 ins; 1 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/20962.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20962/head:pull/20962

PR: https://git.openjdk.org/jdk/pull/20962