[IR] Remove unnecessary includes (NFC)

Author: kazutakahirata

llvm/include/llvm/IR/Dominators.h

@@ -16,15 +16,13 @@
 
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/ADT/ilist_iterator.h"
-#include "llvm/ADT/iterator_range.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/PassManager.h"

llvm/include/llvm/IR/GetElementPtrTypeIterator.h

@@ -20,7 +20,6 @@
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/User.h"
 #include "llvm/Support/Casting.h"
-#include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <iterator>