lisa.wlgen.workload: Propagate exception from _run()'s exit path
Re-raise immediately the exceptions of Workload._run() from within Workload.exit(), instead of just raising upon access to the "output" attribute of the context manager.
Re-raise immediately the exceptions of Workload._run() from within Workload.exit(), instead of just raising upon access to the "output" attribute of the context manager.