execution: PASS
[06:54:37]SIGUSR1 and SIGUSR2 are pending, we can fork
[06:54:37]SIGUSR1 and SIGUSR2 are blocked in child
[06:54:37]SIGUSR1 and SIGUSR2 are not pending in child
[06:54:37]SIGUSR1 and SIGUSR2 are pending, we can fork
[06:54:37]Test passed