src: remove redundant string initialization

PR-URL: #27152
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: gengjiawen

src/node_report_utils.cc

@@ -233,7 +233,7 @@ std::string EscapeJsonChars(const std::string& str) {
       "\\u001a", "\\u001b", "\\u001c", "\\u001d", "\\u001e", "\\u001f"
   };
 
-  std::string ret = "";
+  std::string ret;
   size_t last_pos = 0;
   size_t pos = 0;
   for (; pos < str.size(); ++pos) {