[CRIU] [PATCH 00/13] C/R for threads blocked signals v3

[Cyrill Gorcunov]

Updates

 1) use gettid directly in parasite code
 2) use struct pstree in parasite_infect_seized early
 3) due to 1) the parasite_thread_args dropped out
 4) add comment about -ENOENT in parasite_fini_threads_seized
 5) add explanation why dump_thread were moved
 6) early check for use_sig_blocked in dump_thread
 7) add separate test case pthread01

Not addressed

 1) find_thread_state can be called as declaration argument,
    no need for addition lines
 2) restore_thread_common remains untouched since no sane
    arguments for change were provided

Please review, thanks.