I am pretty certain (though I haven't actually tried it myself) that you should still be able to execute tests from command line (build server) even if your Dev edition is deactivated. The license check is hooked into the UI, not the command line tools. The Run-Time Edition does not require activation or any other sort of licensing check. We trust our customers to purchase the correct number of licenses to stay legal.
Give that a shot and let me know your results... i.e. go ahead and deactivate Dev edition then try executing the build on the same machine.
I don't thing the new scheduling server feature will solve the problem you're trying to achieve. It is intended to kick off running tests on a testing agent computer, i.e. one with at least Run-Time already installed and the tests loaded onto it. It can be used to replace a build server/continuous integration server.
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