fix bug 3313505
Shader cache cleanup could occur in wrong thread
during RS teardown.

Change-Id: Iffed41de046147db30885e6815826e3b640020c1
diff --git a/rsContext.cpp b/rsContext.cpp
index 22c73fe..c437d72 100644
--- a/rsContext.cpp
+++ b/rsContext.cpp
@@ -535,6 +535,7 @@
          mStateFragment.deinit(this);
          mStateFragmentStore.deinit(this);
          mStateFont.deinit(this);
+         mShaderCache.cleanupAll();
     }
     ObjectBase::zeroAllUserRef(this);
     LOGV("destroyWorkerThreadResources 2");