Add timeout for teardown_test

Currently teardown test will stuck at stop stack when ValueError
occured in neighbor test. Add timeout to teardown will allow us to
capture snoop log and further debug neighbor test failures.

Bug: 208712935
Test: cert/run
Tag: #gd-refactor
Change-Id: I0dab000a888e23c2f76b0a342039ecb0ebe64aef