RFR [8]: Fix Minimal VM build

[Aleksey Shipilev]

Minimal VM fails to build after recent backports, because Shenandoah flags are not accessible:

diff -r 2a8e1c939846 src/share/vm/runtime/arguments.cpp
--- a/src/share/vm/runtime/arguments.cpp	Fri Sep 21 16:00:18 2018 -0400
+++ b/src/share/vm/runtime/arguments.cpp	Wed Sep 26 09:56:44 2018 +0200
@@ -1775,11 +1775,13 @@
   }
 #endif

+#if INCLUDE_ALL_GCS
   if (UseLargePages && (MaxHeapSize / os::large_page_size()) < ShenandoahHeapRegion::MIN_NUM_REGIONS) {
     warning("Large pages size (" SIZE_FORMAT "K) is too large to afford page-sized regions,
disabling uncommit",
             os::large_page_size() / K);
     FLAG_SET_DEFAULT(ShenandoahUncommit, false);
   }
+#endif

   FLAG_SET_DEFAULT(ParallelGCThreads,
                    Abstract_VM_Version::parallel_worker_threads());


Testing: x86 minimal build

Thanks,
-Aleksey