RFR: 8210235: JvmtiTrace::safe_get_current_thread_name is unsafe in debug builds

[Kim Barrett]

> On Aug 31, 2018, at 2:01 PM, coleen.phillimore at oracle.com wrote:
> 
> Looks good and trivial.

Thanks.

> Coleen
> 
> On 8/30/18 3:24 PM, Kim Barrett wrote:
>> Please review this trivial change to avoid a possible assert, by
>> calling Thread::current_or_null rather than Thread::current in a
>> context where the NULL case is explicitly handled.
>> 
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8210235
>> 
>> Webrev:
>> http://cr.openjdk.java.net/~kbarrett/8210235/open.00/
>> 
>> Testing:
>> Locally (linux-64) verified change builds and ran some tests for
>> smoke.  I couldn't find any tests involving TraceJVMTI.