seccomp: add missing syscall to tests whitelist
seccomp: add missing syscall to tests whitelist

In the seccomp tests the action for non-whitelisted syscalls is
SeccompAction::Errno. With the updated version of Rust a new
syscall is called when running the tests (SYS_futex). Because we
are returning an error for non-whitelisted syscalls, the tests
were hanging as the futex would never be executed successfuly.

Added SYS_futex to the syscall list.

Signed-off-by: Andreea Florescu <f68a7d732e796861f8e79ea704b43a5ee52eddaf@amazon.com>

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