RFR: Skip RESOLVE in SATBBufferClosure if no forwarded objects are in heap

[Aleksey Shipilev]

http://cr.openjdk.java.net/~shade/shenandoah/satb-no-rb/webrev.01/

I see SATBBufferClosure::do_buffer hot in one of the workloads. One of the things that can be helped
there is avoiding RB-inducing RESOLVE when we know there are no forwarded objects in heap. Instead
of reintroducing the whole bunch of template parameters, it is easier to check once before
processing the entire SATB buffer.

Testing: tier3_gc_shenandoah

Thanks,
-Aleksey