RFR: 8235654: JFR leak profiler should not trace through the StringTable

[Kim Barrett]

> On Dec 10, 2019, at 11:22 AM, erik.osterlund at oracle.com wrote:
> 
> Hi,
> 
> The JFR leak profiler finds strong reference chains to object samples. Weirdly enough, it walks the StringTable roots. But these oops are phantomly reachable. So they should arguably be excluded from the root snapshot.This incorrect use of StringTable::oops_do is the only use of StringTable::oops_do, so I'm removing that function.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8235654
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8235654/webrev.00/
> 
> Thanks,
> /Erik

Looks good.