PY3 migration - blinkpy.web_tests.port unit tests.

Failures from 104 to 3 - 1 test is flaky.
vpython3 ./run_blinkpy_tests.py blinkpy.web_tests.port

Bug: 1218641

Change-Id: I3ec03d55ee860d4f47c41453f316881680ae1f86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3055774


Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Preethi Mohan <preethim@google.com>
Cr-Commit-Position: refs/heads/master@{#906348}