hg: jdk/sandbox: 8246373: AArch64: Refactor register spilling code in ZGC barriers

[chris.hegarty at oracle.com]

Changeset: 968f7a92013d
Author:    smonteith
Date:      2020-07-24 09:00 +0800
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/968f7a92013d

8246373: AArch64: Refactor register spilling code in ZGC barriers
Summary: Tidy up code spilling registers, reduce in some cases.
Reviewed-by: aph, eosterlund

! src/hotspot/cpu/aarch64/gc/z/zBarrierSetAssembler_aarch64.cpp
! src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
! src/hotspot/cpu/aarch64/macroAssembler_aarch64.hpp