[jfx17u] RFR: 8270479: WebKit 612.1 build fails with Visual Studio 2017

[Kevin Rushforth]

Clean backport to `jfx17u`. This has been tested on all platforms along with other pending fixes in the `test-kcr-17.0.1` branch.

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Commit messages:
 - 8270479: WebKit 612.1 build fails with Visual Studio 2017

Changes: https://git.openjdk.java.net/jfx17u/pull/7/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx17u&pr=7&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8270479
  Stats: 21 lines in 3 files changed: 21 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx17u/pull/7.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx17u pull/7/head:pull/7

PR: https://git.openjdk.java.net/jfx17u/pull/7