[jfx17u] RFR: 8299977: Update WebKit to 615.1

Sat Feb 11 15:03:01 UTC 2023

Clean backport. Tested in connection with 3 other WebKit fixes in the `test-kcr-17.0.7` branch, including a successful CI build. I also verfied that the native WebKit code is identical to mainline jfx after applying all patches (excluding a couple of copyright years).

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Commit messages:
 - 8299977: Update WebKit to 615.1

Changes: https://git.openjdk.org/jfx17u/pull/112/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx17u&pr=112&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299977
  Stats: 197124 lines in 5579 files changed: 116283 ins; 42814 del; 38027 mod
  Patch: https://git.openjdk.org/jfx17u/pull/112.diff
  Fetch: git fetch https://git.openjdk.org/jfx17u pull/112/head:pull/112

PR: https://git.openjdk.org/jfx17u/pull/112