Make CheckJNI and JNI workarounds mutually exclusive...

...in the opposite direction; needing workarounds turns off CheckJNI.
This isn't necessarily a good idea, but I like the cleanup parts of
this change.

Change-Id: I708235ea3e5cc35ef90b01dd810e097e3ff9dd26
diff --git a/src/dalvik_system_VMStack.cc b/src/dalvik_system_VMStack.cc
index a83ad45..8560c22 100644
--- a/src/dalvik_system_VMStack.cc
+++ b/src/dalvik_system_VMStack.cc
@@ -18,6 +18,7 @@
 #include "class_loader.h"
 #include "object.h"
 #include "scoped_heap_lock.h"
+#include "scoped_thread_list_lock.h"
 #include "thread_list.h"
 
 #include "JniConstants.h" // Last to avoid problems with LOG redefinition.