RFR: 8236626: Update copyright header for files modified in 2019

[Kevin Rushforth]

Simple fix to update the copyright year in the one file that was changed in 2019 after the last update of the year.

@arapte can you please review?

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Commits:
 - c1d9b8ef: 8236626: Update copyright header for files modified in 2019

Changes: https://git.openjdk.java.net/jfx/pull/76/files
 Webrev: https://webrevs.openjdk.java.net/jfx/76/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8236626
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jfx/pull/76.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/76/head:pull/76

PR: https://git.openjdk.java.net/jfx/pull/76