The mysql-server package on Ubuntu16.04 was recently updated to disallow
unauthenticated root user login over tcp/ip. This, coupled with pymysql
using tcp/ip whenever host and port is specified causes us to fail to
connect to the database when testing Python3 on Ubuntu16.04.
The fix is to use the unix socket instead.
* Update Shippable integration test groups.
* Update integration test group aliases.
* Rebalance AWS and Azure tests with extra group.
* Rebalance Windows tests with another group.
This change corrects problems reported by the `yamllint` linter.
Since key duplication problems were removed in 4d48711, this commit
mainly fixes trailing spaces and extra empty lines at beginning/end of
files.