RFR: 8301604: Replace Collections.unmodifiableList with List.of [v2]

[Glavo]

> `List.of` is cleaner, and can slightly reduce the memory footprint for lists of one or two elements.
> 
> Because `List.of` can only store non-null elements, I have only replaced a few usage.
> 
> Can someone open an Issue on JBS for me?

Glavo has updated the pull request incrementally with two additional commits since the last revision:

 - Update FileChooser
 - Update getTracks

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1012/files
  - new: https://git.openjdk.org/jfx/pull/1012/files/b7482f9a..33e22df6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1012&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1012&range=00-01

  Stats: 33 lines in 2 files changed: 1 ins; 23 del; 9 mod
  Patch: https://git.openjdk.org/jfx/pull/1012.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1012/head:pull/1012

PR: https://git.openjdk.org/jfx/pull/1012