RFR: 8366739: ToolBar: overflow menu with fractional scale (2) [v2]

[Cormac Redmond]

> Fix overflow menu triggering due to floating-point precision error.
> 
> At 1.25 display scaling on Windows, floating-point comparison errors (e.g. 109.60000000000001 > 109.6) cause the overflow menu to appear when the lefthand value is regarded as larger than the righthand value.
> 
> These should be treated as equal (and therefore not display the overflow menu).
> 
> This bug can happen in both horizontal and vertical toolbar orientation.
> 
> The new tests added fail without this fix, and pass with it. An existing test has been re-factored slightly to allow re-use and more flexibility in specifying the scene's root node.

Cormac Redmond has updated the pull request incrementally with one additional commit since the last revision:

  8366739: organizeOverflow() is now snapping length inside  after floating-point manipulation. Also, simplifying previous commit fix in getOverflowNodeIndex() regarding snapping x.

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Changes:
  - all: https://git.openjdk.org/jfx/pull/2016/files
  - new: https://git.openjdk.org/jfx/pull/2016/files/18bda080..d77d2c77

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=2016&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=2016&range=00-01

  Stats: 6 lines in 1 file changed: 1 ins; 1 del; 4 mod
  Patch: https://git.openjdk.org/jfx/pull/2016.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/2016/head:pull/2016

PR: https://git.openjdk.org/jfx/pull/2016