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. ------------- 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
