[ARM] Don't include IRBuilder.h in ARMISelLowering.h (NFC)

Just a forward declaration is sufficient.

Author: nikic

llvm/lib/Target/ARM/ARMISelLowering.h

@@ -27,7 +27,6 @@
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/Support/CodeGen.h"
 #include <optional>
@@ -42,6 +41,7 @@ class FunctionLoweringInfo;
 class GlobalValue;
 class InstrItineraryData;
 class Instruction;
+class IRBuilderBase;
 class MachineBasicBlock;
 class MachineInstr;
 class SelectionDAG;

llvm/lib/Target/ARM/ARMParallelDSP.cpp

@@ -26,6 +26,7 @@
 #include "llvm/CodeGen/TargetPassConfig.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicsARM.h"
+#include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/NoFolder.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/Pass.h"