RFR: 8235364: Update copyright header for files modified in 2019

[Kevin Rushforth]

Update the last-modified year in the copyright header to 2019 for files that were modified this year without updating the year in the copyright header.

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Commits:
 - 9c6e0a64: 8235364: Update copyright header for files modified in 2019

Changes: https://git.openjdk.java.net/jfx/pull/72/files
 Webrev: https://webrevs.openjdk.java.net/jfx/72/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8235364
  Stats: 73 lines in 73 files changed: 0 ins; 0 del; 73 mod
  Patch: https://git.openjdk.java.net/jfx/pull/72.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/72/head:pull/72

PR: https://git.openjdk.java.net/jfx/pull/72