On aix/ppc64, if the server closes before the client calls Accept,
this test will fail.

Increasing the time before the server closes should resolve this
timeout.

Updates #29685

Change-Id: Iebb849d694fc9c37cf216ce1f0b8741249b98016
Reviewed-on: https://go-review.googlesource.com/c/158038Reviewed-by: Ian Lance Taylor <iant@golang.org>