hg: jdk/jdk: 8201785: Make ModRefBarrierSetAssembler abstract on all platforms

[ashipile at redhat.com]

Changeset: ac761df837c7
Author:    shade
Date:      2018-04-19 12:02 +0200
URL:       http://hg.openjdk.java.net/jdk/jdk/rev/ac761df837c7

8201785: Make ModRefBarrierSetAssembler abstract on all platforms
Reviewed-by: eosterlund, pliden, mdoerr

! src/hotspot/cpu/aarch64/gc/shared/modRefBarrierSetAssembler_aarch64.cpp
! src/hotspot/cpu/aarch64/gc/shared/modRefBarrierSetAssembler_aarch64.hpp
! src/hotspot/cpu/ppc/gc/shared/modRefBarrierSetAssembler_ppc.cpp
! src/hotspot/cpu/ppc/gc/shared/modRefBarrierSetAssembler_ppc.hpp
! src/hotspot/cpu/s390/gc/shared/modRefBarrierSetAssembler_s390.cpp
! src/hotspot/cpu/s390/gc/shared/modRefBarrierSetAssembler_s390.hpp