Add code to wait for the bound port to open and close correctly, removing race
conditions.

BUG=test reliability
TEST=better

Review URL: http://codereview.chromium.org/6627013

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@76966 0039d316-1c4b-4281-b951-d872f2087c98