RFR: 8337246: SpinnerSkin does not consume ENTER KeyEvent when editor ActionEvent is consumed

[Andy Goryachev]

Enable backpropagation of `isConsumed` flag to the ancestor(s) of events cloned via `Event.copyFor()`.

This change has a minimal API impact and allows for a fine-grained control of when to propagate and when not to propagate.

The proposed change could make [JDK-8303209](https://bugs.openjdk.org/browse/JDK-8303209) unnecessary.

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Commit messages:
 - only if consumed
 - only when consumed
 - propagate
 - cleanup
 - simpler
 - event helper
 - copy for test
 - propagate consume action

Changes: https://git.openjdk.org/jfx/pull/1523/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1523&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337246
  Stats: 117 lines in 4 files changed: 102 ins; 4 del; 11 mod
  Patch: https://git.openjdk.org/jfx/pull/1523.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1523/head:pull/1523

PR: https://git.openjdk.org/jfx/pull/1523