RFR: 8215097: Do not create NonJavaThreads before BarrierSet

[Kim Barrett]

> On Dec 10, 2018, at 4:38 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
>> On Dec 9, 2018, at 5:05 PM, David Holmes <david.holmes at oracle.com> wrote:
>> 
>> Didn't realize you were going to tackle this so soon. I was just ironing out the wrinkles in 8214097 before sending it for review later today. :)
> 
> It turned out to be pretty easy.  And I thought there was some chance that it would help with 8214097.
> 
> 
>> Everything else seems fine. (I'll be reworking the BarrierSet creation assertion as part of 8214097.)
> 
> Thanks.
> 
> Is there actually any further change to BarrierSet installation needed for 8214097?  I guess I will be finding out shortly, when your RFR comes out.

I should have skimmed ahead in my mailbox; your RFR is already available in preliminary form.

I’d forgotten how much bootstrapping clunkiness was needed for 8214097 without this change.
So yeah, looks like doing mine first does help yours.

Looking at yours, I kind of want the remaining bootstrapping in mine to use your change to set_as_starting_thread,
(e.g. use your new _starting_thread to recognize it), except I think that function is called too late to use for that purpose.