test: investigate async-hooks/test-tcpwrap for flakiness on Linux #12997

1366	async-hooks/test-tcpwrap	
duration_ms	0.172
severity	fail
stack	assert.js:92
  throw new AssertionError({
  ^

AssertionError [ERR_ASSERTION]: 1 TCPCONNECTWRAP present when client is connecting
    at Object.<anonymous> (/home/iojs/build/workspace/node-test-commit-linux/nodes/fedora23/test/async-hooks/test-tcpwrap.js:55:10)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Function.Module.runMain (module.js:605:10)
    at startup (bootstrap_node.js:144:16)
    at bootstrap_node.js:561:3