6863023: need non-perm oops in code cache for JSR 292

Make a special root-list for those few nmethods which might contain non-perm oops.

Reviewed-by: twisti, kvn, never, jmasa, ysr

hotspot/src/share/vm/gc_implementation/parallelScavenge/pcTasks.hpp

@@ -92,7 +92,8 @@ class MarkFromRootsTask : public GCTask {
     jvmti                 = 7,
     system_dictionary     = 8,
     vm_symbols            = 9,
-    reference_processing  = 10
+    reference_processing  = 10,
+    code_cache            = 11
   };
  private:
   RootType _root_type;