[jfx11u] Integrated: 8281459: WebKit 613.1 build broken on M1

[Kevin Rushforth]

Clean backport to `jfx11u`. I tested this along with the other VS 2019 and WebKit 613.1 fixes together in the `test-kcr-11.0.15` branch.

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Commit messages:
 - 8281459: WebKit 613.1 build broken on M1

Changes: https://git.openjdk.java.net/jfx11u/pull/78/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx11u&pr=78&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8281459
  Stats: 20 lines in 1 file changed: 0 ins; 20 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx11u/pull/78.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx11u pull/78/head:pull/78

PR: https://git.openjdk.java.net/jfx11u/pull/78