We'd like to decrease the default timeout for tests in the Qt Project CI
so that we waste less time waiting for hanging tests.

Tests which genuinely take a long time to run, such as this one, should
have their timeout explicitly set in their .pro file.

Change-Id: I953c161ce5fdce38cf8648243250b118cd74cb5f
Reviewed-by: Toby Tomkins <toby.tomkins@nokia.com>