RFR: 8273969: Memory Leak on the Runnable provided to Platform.startup [v2]

[Florian Kirmaier]

> Probably my most boring PR. ;)
> Setting the lambda to null, after it has been used, fixes the leak.

Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:

  JDK-8273969
  Some changes based on code review

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

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/626/files
  - new: https://git.openjdk.java.net/jfx/pull/626/files/7897fd64..9620ed5e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=626&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=626&range=00-01

  Stats: 103 lines in 2 files changed: 55 ins; 48 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/626.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/626/head:pull/626

PR: https://git.openjdk.java.net/jfx/pull/626