Sort the #include lines for tools/...

Again, tools are trickier to pick the main module header for than
library source files. I've started to follow the pattern of using
LLVMContext.h when it is included as a stub for program source files.

llvm-svn: 169252
diff --git a/llvm/tools/llvm-diff/DiffConsumer.h b/llvm/tools/llvm-diff/DiffConsumer.h
index 98e369b..6c2209f 100644
--- a/llvm/tools/llvm-diff/DiffConsumer.h
+++ b/llvm/tools/llvm-diff/DiffConsumer.h
@@ -15,12 +15,11 @@
 #define _LLVM_DIFFCONSUMER_H_
 
 #include "DiffLog.h"
-
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
   class Module;