[Rev 01] RFR: 8198402: ToggleButton.setToggleGroup causes memory leak when button is removed via ToggleGroup.getToggles()

[Jesper Skov]

> Make the two ways of associating a ToggleButton with a ToggleGroup interact correctly.
> 
> This fixes https://bugs.openjdk.java.net/browse/JDK-8198402

Jesper Skov has updated the pull request incrementally with three additional commits since the last revision:

 - Fail instead of print message
 - addedToggles list is final
 - Leave unrelated file alone

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/167/files
  - new: https://git.openjdk.java.net/jfx/pull/167/files/1386ad74..10eef05b

Webrevs:
 - full: https://webrevs.openjdk.java.net/jfx/167/webrev.01
 - incr: https://webrevs.openjdk.java.net/jfx/167/webrev.00-01

  Stats: 5 lines in 3 files changed: 0 ins; 3 del; 2 mod
  Patch: https://git.openjdk.java.net/jfx/pull/167.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/167/head:pull/167

PR: https://git.openjdk.java.net/jfx/pull/167