Clean up mutexes on shutdown.

Change-Id: Ib961f954280c27f8858c4d6fb9010cc833bb28d2
diff --git a/src/jni_internal.cc b/src/jni_internal.cc
index c538670..586b541 100644
--- a/src/jni_internal.cc
+++ b/src/jni_internal.cc
@@ -2583,4 +2583,9 @@
       weak_globals(kWeakGlobalsInitial, kWeakGlobalsMax, kWeakGlobal) {
 }
 
+JavaVMExt::~JavaVMExt() {
+  delete globals_lock;
+  delete weak_globals_lock;
+}
+
 }  // namespace art