test: changed var to const in test

Changed outdated var to const in the test file
repl-unexpected-token-recoverable.js

PR-URL: #30434
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

test/parallel/test-repl-unexpected-token-recoverable.js

@@ -10,7 +10,7 @@ const spawn = require('child_process').spawn;
 const args = [ '-i' ];
 const child = spawn(process.execPath, args);
 
-const input = 'var foo = "bar\\\nbaz"';
+const input = 'const foo = "bar\\\nbaz"';
 // Match '...' as well since it marks a multi-line statement
 const expectOut = /> \.\.\. undefined\n/;