test: improve assertion fail messages

PR-URL: #14949
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-stream-inheritance.js

@@ -33,13 +33,19 @@ assert.ok(!(undefined instanceof Writable));
 
 // Simple inheritance check for `Writable` works fine in a subclass constructor.
 function CustomWritable() {
-  assert.ok(this instanceof Writable, 'inherits from Writable');
-  assert.ok(this instanceof CustomWritable, 'inherits from CustomWritable');
+  assert.ok(
+    this instanceof CustomWritable,
+    `${this} does not inherit from CustomWritable`
+  );
+  assert.ok(
+    this instanceof Writable,
+    `${this} does not inherit from Writable`
+  );
 }
 
 Object.setPrototypeOf(CustomWritable, Writable);
 Object.setPrototypeOf(CustomWritable.prototype, Writable.prototype);
 
 new CustomWritable();
 
-assert.throws(CustomWritable, /AssertionError: inherits from Writable/);
+assert.throws(CustomWritable, /AssertionError: undefined does not inherit from CustomWritable/);