RFR: Fix non-PCH build after merge

[Aleksey Shipilev]

Current non-PCH build fails with:

In file included from
/pool/buildbot/slaves/sobornost/shenandoah-jdkX/build/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp:29:0:
/pool/buildbot/slaves/sobornost/shenandoah-jdkX/build/src/hotspot/share/gc/shared/parallelCleaning.hpp:33:15:
error: ‘ParState’ in ‘class OopStorage’ does not name a template type
   OopStorage::ParState<false /* concurrent */, false /* const */> _par_state_string;
               ^~~~~~~~

Fix:

diff -r f3202182671b src/hotspot/share/gc/shared/parallelCleaning.hpp
--- a/src/hotspot/share/gc/shared/parallelCleaning.hpp	Fri Jun 08 13:22:17 2018 -0400
+++ b/src/hotspot/share/gc/shared/parallelCleaning.hpp	Mon Jun 11 13:33:52 2018 +0200
@@ -25,6 +25,7 @@
 #ifndef SHARE_VM_GC_SHARED_PARALLELCLEANING_HPP
 #define SHARE_VM_GC_SHARED_PARALLELCLEANING_HPP

+#include "gc/shared/oopStorageParState.hpp"
 #include "gc/shared/workgroup.hpp"

 class StringSymbolTableUnlinkTask : public AbstractGangTask {

Testing: tier1_gc_shenandoah

Thanks,
-Aleksey