Heads-up: sh/jdk11 aarch64 build failure

[Aleksey Shipilev]

This is due to recent backports:

/home/shade/shenandoah-jdk11/src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp:
In member function ‘virtual void ShenandoahBarrierSetAssembler::arraycopy_epilogue(MacroAssembler*,
DecoratorSet, bool, Register, Register, Register, RegSet)’:
/home/shade/shenandoah-jdk11/src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp:94:14:
error: ‘count’ was not declared in this scope
       __ cbz(count, done);
              ^~~~~

...there is no "count" register there indeed.

-Aleksey