[jfx20u] Integrated: 8301022: Video distortion is observed while playing youtube video

[Kevin Rushforth]

Clean backport to `jfx20u`. Tested in connection with all other WebKit backports in `jfx-20.0.1` branch.

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Commit messages:
 - 8301022: Video distortion is observed while playing youtube video

Changes: https://git.openjdk.org/jfx20u/pull/7/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx20u&pr=7&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301022
  Stats: 1527 lines in 4 files changed: 1527 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx20u/pull/7.diff
  Fetch: git fetch https://git.openjdk.org/jfx20u pull/7/head:pull/7

PR: https://git.openjdk.org/jfx20u/pull/7