readline: fix unit tests

Author: jcubic

lib/internal/readline/utils.js

@@ -195,11 +195,11 @@ function* emitKeys(stream) {
         const cmd = StringPrototypeSlice(s, cmdStart);
         let match;
 
-        if ((match = RegExpPrototypeExec(/^(?:(\d\d?)(?:;(\d))?[~^$]|(\d{3}~))$/, cmd))) {
-          if (match[3]) {
-            code += match[3];
+        if ((match = RegExpPrototypeExec(/^(?:(\d\d?)(?:;(\d))?([~^$])|(\d{3}~))$/, cmd))) {
+          if (match[4]) {
+            code += match[4];
           } else {
-            code += match[1];
+            code += match[1] + match[3];
             modifier = (match[2] || 1) - 1;
           }
         } else if (