Previously, the test that verified that Undertow's access log could be
enabled and was written to the correct file expected the log to be
available as soon as the request to the server had completed. Undertow
writes the access log asynchronously so the test failed intermittently
due to a race between the access log being written and the test
asserting that it exists.

This commit updates the test to wait for up to 10 seconds for the
access log to be available.

See gh-4670