RFR: 8199328: Fix unsafe field accesses in heap dumper

[Thomas Schatzl]

Hi,

On Thu, 2018-03-08 at 15:01 +0100, Per Liden wrote:
> The heap dumper, more specifically the
> DumperSupport::dump_field_value() 
> function, is doing unsafe raw loads of fields in heap objects. Those 
> loads should go thru the access API.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8199328
> Webrev: http://cr.openjdk.java.net/~pliden/8199328/webrev.0/
> 
> Testing: manual dumping using jcmd GC.heap_dump, awaiting hs-tier1-3
> results

  I think this is good, but somebody else should also look into this as
making sure that the right invariants hold for all collectors is
tricky.

Thanks,
  Thomas