RFR (XS): Cancel events should print cause, and fire only once

[Roman Kennke]

Am Freitag, den 25.11.2016, 13:12 +0100 schrieb Aleksey Shipilev:
> Hi,
> 
> This is simple UX improvement that makes sure we only print "Cancel
> GC"
> once, and also print the reason for it:
>   http://cr.openjdk.java.net/~shade/shenandoah/cancel-cause/webrev.01
> /
> 

Ok

Roman