hg: zgc/zgc: ZGC: Clean up ZLoadBarrierStubC1 tmp register allocation

[per.liden at oracle.com]

Changeset: 4020bde00da0
Author:    pliden
Date:      2018-05-08 13:05 +0200
URL:       http://hg.openjdk.java.net/zgc/zgc/rev/4020bde00da0

ZGC: Clean up ZLoadBarrierStubC1 tmp register allocation

! src/hotspot/cpu/sparc/gc/z/zBarrierSetAssembler_sparc.cpp
! src/hotspot/cpu/x86/gc/z/zBarrierSetAssembler_x86.cpp
! src/hotspot/share/gc/z/c1/zBarrierSetC1.cpp