RFR: Fix and enable suspendible workers by default

[Roman Kennke]

> On 10/06/2018 12:18 PM, Roman Kennke wrote:
>> Benchmarks have not shown regressions.
>>
>>> Look at this webrev instead. I remove stray includes in 2 non-Shenandoah
>>> files that slipped in by accident:
>>>
>>> http://cr.openjdk.java.net/~rkennke/fix-enable-susp-workers/webrev.01/
> 
> Looks good, let's go with it.

Have you tried/can you try the failing lucene-solr test with the jdk8u
patch that I've sent?

Roman