fix seccomp test for ARM64

As open syscall is not support on ARM64, change syscall
from 'open' to 'openat' in no_match_name_allow

Signed-off-by: Howard Zhang <howard.zhang@arm.com>

runsc/specutils/seccomp/seccomp_test.go

@@ -169,7 +169,7 @@ var (
 					},
 				},
 			},
-			input:    testInput(nativeArchAuditNo, "open", nil),
+			input:    testInput(nativeArchAuditNo, "openat", nil),
 			expected: uint32(allowAction),
 		},
 		{