AutoScheduler and autotvm.measure.measure_methods.set_cuda_target_arch

AutoScheduler relies on python’s multiprocessing library to propagate the global state to child processes, which used to cause a lot of issues working with other libraries like jupyter. After the introduction of PopenPool, we are able to get things working with Jupyter by strictly isolating processes. It is likely a global state on the main process that is not propagated to popen worker processes