We retired servlets.compat but it is still used in the launchpad.testing and launchpad.testing-war via the test-bundles. For some reason certain tests will fail without it.
As far as I can tell, the servlets.compat is the only reason at this point that we still need the commons.json bundle in the test-bundles.
Due to the fact that we retired servlets.compat, are about to retire commons.json, and can't release anything with commons.json anyways. We should figure out what is going on and find a way to remove the dependency on the servlets.compat bundle in the tests.