RFR: 8088998: XYChart: duplicate child added exception when remove & add a series in several charts [v4]

[Karthik P K]

> While checking for duplicate series addition to the line chart, `setToRemove` value was not considered before throwing exception. Hence code to handling the case of adding the removed series was never run.
> 
> Added condition to check `setToRemove` boolean value before throwing exception. Made changes to call `setChart` method after calling `seriesBeingRemovedIsAdded`. Otherwise chart will not be drawn for the series, only points will be plotted.
> 
> This issue is reproducible only when animation is enabled because timeline will be still running when removed series is added back to the same chart. Since timeline does not run in unit tests, added system test to validate the fix.

Karthik P K has updated the pull request incrementally with one additional commit since the last revision:

  Addressing review comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1015/files
  - new: https://git.openjdk.org/jfx/pull/1015/files/d707f321..146bef2a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1015&range=03
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1015&range=02-03

  Stats: 14 lines in 1 file changed: 11 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1015.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1015/head:pull/1015

PR: https://git.openjdk.org/jfx/pull/1015