ART: disassembler_x86 doesn't recognize NOPs

There are some variations of NOPs which are possible on x86.

Change-Id: I6aab3bc98682e521532cc746f3a371d9c5d98ee8
diff --git a/disassembler/disassembler_x86.h b/disassembler/disassembler_x86.h
index 71c3e41..31b62bc 100644
--- a/disassembler/disassembler_x86.h
+++ b/disassembler/disassembler_x86.h
@@ -33,6 +33,7 @@
   void Dump(std::ostream& os, const uint8_t* begin, const uint8_t* end) OVERRIDE;
 
  private:
+  size_t DumpNops(std::ostream& os, const uint8_t* instr);
   size_t DumpInstruction(std::ostream& os, const uint8_t* instr);
 
   std::string DumpAddress(uint8_t mod, uint8_t rm, uint8_t rex64, uint8_t rex_w, bool no_ops,