Merge bitcoin#11418: Add error string for CLEANSTACK script violation

cee28fb Add error string for CLEANSTACK script violation, preventing an "unknown error" if the CLEANSTACK error condition is set. (Mark Friedenbach)

Pull request description:

  This prevents an unhelpful "unknown error" from being printed in test logs if the CLEANSTACK error condition is set.

Tree-SHA512: cd6764e930184aef3d662e40c67f2ea8aea8552a26d33a567d0315a19d707a82aa2afad9f48ecbb731aa5b77fbbfbd7a6a3a989fdb1424a1181350052ff2a9b5

src/script/script_error.cpp

@@ -69,6 +69,8 @@ const char* ScriptErrorString(const ScriptError serror)
             return "NOPx reserved for soft-fork upgrades";
         case SCRIPT_ERR_PUBKEYTYPE:
             return "Public key is neither compressed or uncompressed";
+        case SCRIPT_ERR_CLEANSTACK:
+            return "Extra items left on stack after execution";
         case SCRIPT_ERR_UNKNOWN_ERROR:
         case SCRIPT_ERR_ERROR_COUNT:
         default: break;