RFR: Print out garbage and cset data with -Xlog:gc+ergo

[Aleksey Shipilev]

Hi,

I would like to have it in product builds:
  http://cr.openjdk.java.net/~shade/shenandoah/policy-print-cset/webrev.01/

Prints:

[39.903s][info][gc,ergo] GC(21) Total Garbage: 8701M
[39.903s][info][gc,ergo] GC(21) Immediate Garbage: 0M, 0 regions
[39.903s][info][gc,ergo] GC(21) Garbage to be collected: 760M (8% of total), 152
regions
[39.903s][info][gc,ergo] GC(21) Live objects to be evacuated: 455M
[39.903s][info][gc,ergo] GC(21) Live/garbage ratio in collected regions: 59%


Thanks,
-Aleksey