Debug tidying some verification fixes.

Weaken verification of signature types to allow unresolved types as
Object. Fix for interface and field store types.

Change-Id: I2dd5debc96fcaa8e0db7de5231b6926729c201fa
diff --git a/src/dex_instruction.h b/src/dex_instruction.h
index 36ea295..5cfd7ef 100644
--- a/src/dex_instruction.h
+++ b/src/dex_instruction.h
@@ -189,11 +189,11 @@
              kVerifySwitchTargets | kVerifyVarArg | kVerifyVarArgRange | kVerifyError));
   }
 
-  // Dump code_units worth of this instruction, padding to code_units for shorter instructions
-  void DumpHex(std::ostream& os, size_t code_units) const;
-
   // Dump decoded version of instruction
-  void Dump(std::ostream& os, const DexFile*) const;
+  std::string DumpString(const DexFile*) const;
+
+  // Dump code_units worth of this instruction, padding to code_units for shorter instructions
+  std::string DumpHex(size_t code_units) const;
 
  private:
   static const char* const kInstructionNames[];