RFR: 8259864: Cleanup unused Prism files

[Johan Vos]

Fix for JDK-8259864
Remove java and native files that are not used/maintained in prism configurations.

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Commit messages:
 - Remove unused prism files.

Changes: https://git.openjdk.java.net/jfx/pull/378/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=378&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259864
  Stats: 2060 lines in 19 files changed: 0 ins; 2059 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/378.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/378/head:pull/378

PR: https://git.openjdk.java.net/jfx/pull/378