RFR: 8334124: Rendering issues with CSS "text-shadow" in WebView

[Oliver Schmidtmer]

On a Shadow state update with cleared shadow, the new values were not transmitted to the Java GraphicsDecoder

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Commit messages:
 - 8334124: Rendering issues with CSS "text-shadow" in WebView

Changes: https://git.openjdk.org/jfx/pull/1547/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1547&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8334124
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1547.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1547/head:pull/1547

PR: https://git.openjdk.org/jfx/pull/1547