Disable coverage reports and enable test IDs for the Djblets test suite.
Review Request #7892 — Created Jan. 17, 2016 and submitted
This turns off coverage reports for Djblets by default, requiring the --with-coverage parameter to enable them (like we require for RBTools and Review Board), reducing the test time to 25% of what it was before. It also enables test IDs, which makes it easy to re-run a failing test without hunting for the proper test function.
Ran the test suite. Saw a huge performance increase, with test IDs and
no coverage report. Then ran again with a coverage report, and saw that.