AIX build broken after 8212611.

"/net/usr.work/openjdk/nb/rs6000_64/nightly/jdk/src/hotspot/share/opto/cfgnode.cpp", line 1452.22: 1540-0129 (S) The qualifier "BarrierSet" is not defined in the current scope.

(As for why did not non-pch build not find this: barrierSet.hpp is included to cfgnode.cpp as a side effect of jfr:

471 ........ /shared/projects/openjdk/jdk-jdk/output-fastdebug-nopch/hotspot/variant-server/gensrc/jfrfiles/jfrEventClasses.hpp
472 ......... /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/jfr/recorder/service/jfrEvent.hpp
477 .......... /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/jfr/writers/jfrNativeEventWriter.hpp
482 ........... /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/jfr/writers/jfrEventWriterHost.inline.hpp
483 ............ /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/jfr/writers/jfrEventWriterHost.hpp
484 ............. /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/jfr/writers/jfrWriterHost.inline.hpp
505 .............. /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/oops/typeArrayOop.inline.hpp
506 ............... /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/oops/access.inline.hpp
507 ................ /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/gc/shared/barrierSetConfig.inline.hpp
508 ................. /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/gc/shared/modRefBarrierSet.inline.hpp
509 .................. /shared/projects/openjdk/jdk-jdk/source/src/hotspot/share/gc/shared/barrierSet.hpp

Since we do not include JFR on AIX, we miss these includes