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/psTasks.hpp

@@ -54,7 +54,8 @@ class ScavengeRootsTask : public GCTask {
     flat_profiler         = 5,
     system_dictionary     = 6,
     management            = 7,
-    jvmti                 = 8
+    jvmti                 = 8,
+    code_cache            = 9
   };
  private:
   RootType _root_type;