RFR: Rehash ShenandoahHeap section in hs_err

[Aleksey Shipilev]

Turns out, recent heap region formatting change omitted printing out the header
ShenandoahHeap data in hs_err. Fixed that, plus added a few more missing things:
  http://cr.openjdk.java.net/~shade/shenandoah/hserr-printout/webrev.01/

Sample hs_err:
  http://cr.openjdk.java.net/~shade/shenandoah/hserr-printout/hs_err_pid4475.log

Thanks,
-Aleksey