Rename OptimizationDiagnosticInfo.* to OptimizationRemarkEmitter.*

Sync it up with the name of the class actually defined here.  This has been
bothering me for a while...

llvm-svn: 315249
diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp
index 5bef247..e9529e3 100644
--- a/llvm/lib/CodeGen/RegAllocGreedy.cpp
+++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp
@@ -30,7 +30,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Analysis/OptimizationDiagnosticInfo.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/CodeGen/CalcSpillWeights.h"
 #include "llvm/CodeGen/EdgeBundles.h"
 #include "llvm/CodeGen/LiveInterval.h"