Fix simarm product build on Windows

runtime/vm/disassembler.h

Index: runtime/vm/disassembler.h
diff --git a/runtime/vm/disassembler.h b/runtime/vm/disassembler.h
index 283f16ed3b9f28c4a28417a17c9afc04a05ae6bf..8b17c67a85bc84058cb193a821fa67d74009b62b 100644
--- a/runtime/vm/disassembler.h
+++ b/runtime/vm/disassembler.h
@@ -102,15 +102,23 @@ class Disassembler : public AllStatic {
   }
 
   static void Disassemble(uword start, uword end, const Code& code) {
+#ifndef PRODUCT
     DisassembleToStdout stdout_formatter;
     LogBlock lb;
     Disassemble(start, end, &stdout_formatter, code);
+#else
+    UNREACHABLE();
+#endif
   }
 
   static void Disassemble(uword start, uword end) {
+#ifndef PRODUCT
     DisassembleToStdout stdout_formatter;
     LogBlock lb;
     Disassemble(start, end, &stdout_formatter);
+#else
+    UNREACHABLE();
+#endif
   }
 
   // Decodes one instruction.