Reclassify the pin table as a VM internal root.  The native stack
classification requires an associated thread but are not directly
associated with a thread.  If we encounter an object in the pin table
during an hprof dump hat will fail.

Change-Id: I9e49f88cd632584b5818c702cf80f3f96ec5da85
diff --git a/vm/alloc/Visit.c b/vm/alloc/Visit.c
index 5371177..7e3ae34 100644
--- a/vm/alloc/Visit.c
+++ b/vm/alloc/Visit.c
@@ -217,7 +217,7 @@
     visitHashTable(visitor, gDvm.internedStrings, ROOT_INTERNED_STRING, arg);
     visitHashTable(visitor, gDvm.literalStrings, ROOT_INTERNED_STRING, arg);
     visitReferenceTable(visitor, &gDvm.jniGlobalRefTable, 0, ROOT_JNI_GLOBAL, arg);
-    visitReferenceTable(visitor, &gDvm.jniPinRefTable, 0, ROOT_NATIVE_STACK, arg);
+    visitReferenceTable(visitor, &gDvm.jniPinRefTable, 0, ROOT_VM_INTERNAL, arg);
     visitLargeHeapRefTable(visitor, gDvm.gcHeap->referenceOperations, ROOT_REFERENCE_CLEANUP, arg);
     visitLargeHeapRefTable(visitor, gDvm.gcHeap->pendingFinalizationRefs, ROOT_FINALIZING, arg);
     visitThreads(visitor, arg);