[8u] Post-commit review: RT-35172: Add unit test for batching large number of runLater operations

[Kevin Rushforth]

Anthony & Steve,

If you are interested, I added a unit test for batching large numbers of 
runLater operations (as a follow up to RT-21569 
<https://javafx-jira.kenai.com/browse/RT-21569>), which in FX 8 works on 
Windows platforms only because of the InvokeLaterDispatcher.

JIRA:  https://javafx-jira.kenai.com/browse/RT-35172
Changeset:  http://hg.openjdk.java.net/openjfx/8u-dev/rt/rev/acc894d665a6

As I wrote in the JIRA:

While instrumenting the code, a comment indicates that for SWT 
embedding, the InvokeLaterDispatcher is disabled, so this might be an 
issue on Windows in that mode. Perhaps a follow-up issue is in order, 
although in practice I'm not sure we have ever seen this failure.

-- Kevin