RFR: Cannot do more than 1000 Full GCs

[Aleksey Shipilev]

...no, really. That's because we use the wrong timer for StringDictionary cleanup, which makes it
overflow the assert in TimePartitions::report_gc_phase_start:
   assert(_phases->length() <= 1000, "Too many recored phases?");

Fix and test:
  http://cr.openjdk.java.net/~shade/shenandoah/lots-of-cycles/webrev.01/

Testing: hotspot_gc_shenandoah

Thanks,
-Aleksey