refactor: Avoid duplicate map lookup in ScriptToAsmStr

Author: promag

src/core_write.cpp

@@ -111,8 +111,9 @@ std::string ScriptToAsmStr(const CScript& script, const bool fAttemptSighashDeco
                     // checks in CheckSignatureEncoding.
                     if (CheckSignatureEncoding(vch, SCRIPT_VERIFY_STRICTENC, nullptr)) {
                         const unsigned char chSigHashType = vch.back();
-                        if (mapSigHashTypes.count(chSigHashType)) {
-                            strSigHashDecode = "[" + mapSigHashTypes.find(chSigHashType)->second + "]";
+                        const auto it = mapSigHashTypes.find(chSigHashType);
+                        if (it != mapSigHashTypes.end()) {
+                            strSigHashDecode = "[" + it->second + "]";
                             vch.pop_back(); // remove the sighash type byte. it will be replaced by the decode.
                         }
                     }