add some #includes that will soon be needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133195 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp

@@ -14,6 +14,7 @@
 #include "llvm/Function.h"
 #include "llvm/GlobalValue.h"
 #include "llvm/LLVMContext.h"
+#include "llvm/ADT/ArrayRef.h"
 
 using namespace llvm;