Move DomTreeUpdater from IR to Analysis

DomTreeUpdater depends on headers from Analysis, but is in IR.  This is a
layering violation since Analysis depends on IR.  Relocate this code from IR
to Analysis to fix the layering violation.

llvm-svn: 353265
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 57af3d1..5e661ae 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -14,6 +14,7 @@
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/BasicAliasAnalysis.h"
+#include "llvm/Analysis/DomTreeUpdater.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -26,7 +27,6 @@
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/DIBuilder.h"
-#include "llvm/IR/DomTreeUpdater.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"