[Bitcode] Add missing includes in llvm-dis-fuzzer

Probably missed as part of some recent header cleanup.

Author: nikic

llvm/tools/llvm-dis-fuzzer/llvm-dis-fuzzer.cpp

@@ -11,6 +11,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Bitcode/BitcodeReader.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
 #include "llvm/Support/MemoryBuffer.h"
 
 using namespace llvm;