RFR: Early update references phase

[Roman Kennke]

Am 28.03.2017 um 17:20 schrieb Aleksey Shipilev:
> On 03/28/2017 04:57 PM, Roman Kennke wrote:
>> http://cr.openjdk.java.net/~rkennke/update-refs/webrev.00/
> Looks good.
>
> There is no need to update references during concmark if heuristics called to do
> this early, right?
Nope. And it is implemented like this I think.

Roman