[jfx25u] RFR: 8367578: Additional WebKit 622.1 fixes from WebKitGTK 2.48.7

[Jay Bhaskar]

A clean backport for jfx25u-cpu-open. The fix is a cherry pick of webkit gtk 2.48.6, 2.48.7 and all tests are ok.

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Commit messages:
 - Backport adb6c11e34c6e08e158e8a9ec6aa769ad9de9a4e

Changes: https://git.openjdk.org/jfx25u/pull/25/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx25u&pr=25&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367578
  Stats: 233 lines in 41 files changed: 141 ins; 36 del; 56 mod
  Patch: https://git.openjdk.org/jfx25u/pull/25.diff
  Fetch: git fetch https://git.openjdk.org/jfx25u.git pull/25/head:pull/25

PR: https://git.openjdk.org/jfx25u/pull/25