test: improve assertion error message in test-debug-usage

PR-URL: #30913
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-debug-usage.js

@@ -24,5 +24,8 @@ child.on('exit', common.mustCall(function(code) {
   const outputLines = actualUsageMessage.split('\n');
   assert.strictEqual(code, 1);
   for (let i = 0; i < expectedLines.length; i++)
-    assert(expectedLines[i].test(outputLines[i]));
+    assert.ok(
+      expectedLines[i].test(outputLines[i]),
+      `${outputLines[i]} did not match ${expectedLines[i]}`
+    );
 }));