Unit test: tweak secure connection check.

The main wikipedia page can be slow to load and thus triggers the timeout.
Let's use the fast Google site so that we don't get flaky outcome.

Issue #10882: https://github.com/ariya/phantomjs/issues/10882
Unit tests: terminate any web servers after finishing the tests.

Issue #11163: https://github.com/ariya/phantomjs/issues/11163
Issue #11243: https://github.com/ariya/phantomjs/issues/11243
Unit tests: robustify the tests of PDF, GIF, PNG, JPEG rendering.

Issue #10973 https://github.com/ariya/phantomjs/issues/10973
Unit test: secure connection check becomes async.

Issue #10882: https://github.com/ariya/phantomjs/issues/10882
Unit tests: reduce the flakiness of loading progress tests.

For whatever reason, swapping the order with the render() tests solve the
intermittent random failures. Also, split the tests between loading
start and finish checks (to better recognize which one is failing, if
there is a failure), also make the tests more asynchoronous.

https://github.com/ariya/phantomjs/issues/11091
Include all the changes from 1.9.1.