Acquire locks when dealing when build commands cache
At the moment two methods core.lkvog.LKVOG#process_linux_kernel_build_cmd_desc and core.lkvog.LKVOG#_find_cc_full_desc_files_ operates with build commands cache linux_kernel_build_cmd_out_file_desc without any explicit locking while each of them performs several nonatomic actions. Maybe this can be a reason of extremely rare data races (e.g. #8664, although I'm not sure that was a data race...).
I suppose to explicitly acquire locks around all operations with shared dictionary. To do that it is most likely required to introduce multiprocessing.managers.SyncManager.Lock.