[WebAssembly] Remove unused headers in MCWasmObjectWriter

include/llvm/MC/MCWasmObjectWriter.h

 //===-- llvm/MC/MCWasmObjectWriter.h - Wasm Object Writer -------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_MC_MCWASMOBJECTWRITER_H
 #define LLVM_MC_MCWASMOBJECTWRITER_H
 
-#include "llvm/ADT/Triple.h"
-#include "llvm/BinaryFormat/Wasm.h"
-#include "llvm/Support/DataTypes.h"
+#include <memory>
 
 namespace llvm {
 
 class MCFixup;
 class MCObjectWriter;
 class MCValue;
 class raw_pwrite_stream;
 

lib/MC/MCWasmObjectTargetWriter.cpp

 //===-- MCWasmObjectTargetWriter.cpp - Wasm Target Writer Subclass --------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/MC/MCExpr.h"
-#include "llvm/MC/MCValue.h"
 #include "llvm/MC/MCWasmObjectWriter.h"
 
 using namespace llvm;
 
 MCWasmObjectTargetWriter::MCWasmObjectTargetWriter(bool Is64Bit_)
     : Is64Bit(Is64Bit_) {}
 
 // Pin the vtable to this object file
 MCWasmObjectTargetWriter::~MCWasmObjectTargetWriter() = default;