[jfx17u] RFR: 8303680: Virtual Flow freezes after calling scrollTo and scrollPixels in succession

[Jose Pereda]

Clean backport of 8303680: Virtual Flow freezes after calling scrollTo and scrollPixels in succession

Reviewed-by: angorya, jvos

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Commit messages:
 - 8303680: Virtual Flow freezes after calling scrollTo and scrollPixels in succession

Changes: https://git.openjdk.org/jfx17u/pull/155/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx17u&pr=155&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303680
  Stats: 43 lines in 2 files changed: 42 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jfx17u/pull/155.diff
  Fetch: git fetch https://git.openjdk.org/jfx17u.git pull/155/head:pull/155

PR: https://git.openjdk.org/jfx17u/pull/155