test: unmark flaky test

This effectively reverts 5c475a7 and
75095d7.

PR-URL: #16758
Fixes: https://github.com/node/issues/16210
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

Author: addaleax

test/parallel/parallel.status

@@ -5,8 +5,6 @@ prefix parallel
 # sample-test                        : PASS,FLAKY
 
 [true] # This section applies to all platforms
-# https://github.com/nodejs/node/issues/16210
-test-async-wrap-uncaughtexception: PASS,FLAKY
 
 [$system==win32]