Race in MasterRpcServices.getProcedureResult

In ProcedureExecutor, we only consider a procedure to be finished when it is removed from the procedures map. But in MasterRpcServices.getProcedureResult, we will use the state of the procedure to determine whether it is finished. If setFailure is called, the procedure may enter the FAILED state which indicates it is finished before being removed from the procedure map, and then causes an assertion when we calling ProcedureExecutor.removeResult in MasterRpcServices.getProcedureResult.