src: add missing new line to printed message

PR-URL: https://github.com/nodejs/node/pull/13940
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>

src/node.cc

@@ -4372,7 +4372,7 @@ void Init(int* argc,
   if (!i18n::InitializeICUDirectory(icu_data_dir)) {
     fprintf(stderr,
             "%s: could not initialize ICU "
-            "(check NODE_ICU_DATA or --icu-data-dir parameters)",
+            "(check NODE_ICU_DATA or --icu-data-dir parameters)\n",
             argv[0]);
     exit(9);
   }

test/parallel/test-icu-data-dir.js

@@ -9,7 +9,7 @@ const { spawnSync } = require('child_process');
 
 const expected =
     'could not initialize ICU ' +
-    '(check NODE_ICU_DATA or --icu-data-dir parameters)';
+    '(check NODE_ICU_DATA or --icu-data-dir parameters)\n';
 
 {
   const child = spawnSync(process.execPath, ['--icu-data-dir=/', '-e', '0']);