[IVDescriptors] Remove IRBuilder.h include; NFC

IVDescriptors.h itself does not reference IRBuilder at all.
Move the include into transformation passes that do.

include/llvm/Analysis/IVDescriptors.h

@@ -24,7 +24,6 @@
 #include "llvm/Analysis/MustExecute.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Dominators.h"
-#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstrTypes.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/ValueHandle.h"

lib/Transforms/Scalar/LoopSimplifyCFG.cpp

@@ -30,6 +30,7 @@
 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Dominators.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Transforms/Scalar.h"

lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

@@ -35,6 +35,7 @@
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Use.h"
 #include "llvm/IR/Value.h"
 #include "llvm/InitializePasses.h"