RFR: Immediate garbage ratio should not go over 100%

[Roman Kennke]

Am 11.04.2018 um 11:49 schrieb Aleksey Shipilev:
> http://cr.openjdk.java.net/~shade/shenandoah/immediate-acct/webrev.01/
> 
> Stumbled upon this bug during logging improvements. This is mostly benign, but heuristics may decide
> to immediate-shortcut when it really should not. Happens when lots of dead humongous regions are
> present.
> 
> Testing: hotspot_gc_shenandoah
> 
> Thanks,
> -Aleksey
> 

Ok