[jfx17u] RFR: 8320267: WebView crashes on macOS 11 with WebKit 616.1

[Jose Pereda]

Clean backport of 8320267: WebView crashes on macOS 11 with WebKit 616.1
Reviewed-by: jbhaskar, jpereda

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Commit messages:
 - 8320267: WebView crashes on macOS 11 with WebKit 616.1

Changes: https://git.openjdk.org/jfx17u/pull/168/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx17u&pr=168&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320267
  Stats: 191 lines in 2 files changed: 15 ins; 171 del; 5 mod
  Patch: https://git.openjdk.org/jfx17u/pull/168.diff
  Fetch: git fetch https://git.openjdk.org/jfx17u.git pull/168/head:pull/168

PR: https://git.openjdk.org/jfx17u/pull/168