test: fix watch mode test flake

PR-URL: nodejs#44739
Backport-PR-URL: nodejs#44815
Fixes: nodejs#44735
Reviewed-By: Erick Wendel <erick.workspace@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

test/sequential/test-watch-mode.mjs

@@ -94,8 +94,10 @@ describe('watch mode', { concurrency: true, timeout: 60_0000 }, () => {
     const file = fixtures.path('watch-mode/failing.js');
     const { stderr, stdout } = await spawnWithRestarts({ file });
 
+    // Use match first to pretty print diff on failure
     assert.match(stderr, /Error: fails\r?\n/);
-    assert.strictEqual(stderr.match(/Error: fails\r?\n/g).length, 2);
+    // Test that failures happen once per restart
+    assert(stderr.match(/Error: fails\r?\n/g).length >= 2);
     assertRestartedCorrectly({
       stdout,
       messages: { completed: `Failed running ${inspect(file)}`, restarted: `Restarting ${inspect(file)}` },