Ensure daemon under test does not perform any initial build work when profiled or benchmarked

[adammurdoch]

When a given build has never been run with the version of Gradle under test, for the specified Gradle user home, the daemon under test will include state/noise from the initial work of downloading stuff, compiling scripts, and so on.

Previously, we used to do a clean build and shut down the daemons, prior to benchmarking or profiling, but this was removed. We should add an initial run of the scenario, then shutdown the daemon, then benchmark or profile. This initial run does not necessarily need to be a clean build, but it should do something similar to the scenario under test.

[adammurdoch]

just a correction: the initial setup was done prior to benchmarking, but not profiling.

[lptr]

Would #201 solve this?