Prune two MachineInstr.h includes, fix up deps

MachineInstr.h included AliasAnalysis.h, which includes a world of IR
constructs mostly unneeded in CodeGen. Prune it. Same for
DebugInfoMetadata.h.

Noticed with -ftime-trace.

llvm-svn: 375311
diff --git a/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp b/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp
index bd3e344..6629000 100644
--- a/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp
+++ b/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "MIRVRegNamerUtils.h"
+#include "llvm/Support/Debug.h"
 
 using namespace llvm;