Also clear the JNI weak global reference table on shutdown.

Change-Id: I6644bd3cbd60024db60a46f9ead4d50a3112f751
diff --git a/vm/Jni.c b/vm/Jni.c
index b86ace8..f0cc730 100644
--- a/vm/Jni.c
+++ b/vm/Jni.c
@@ -338,6 +338,7 @@
 {
 #ifdef USE_INDIRECT_REF
     dvmClearIndirectRefTable(&gDvm.jniGlobalRefTable);
+    dvmClearIndirectRefTable(&gDvm.jniWeakGlobalRefTable);
 #else
     dvmClearReferenceTable(&gDvm.jniGlobalRefTable);
 #endif