crt: tests: update t__sys_errlist

Previously, this test would simply print an error message if `_sys_errlist`
returns `NULL`. Instead, exit with non-zero to signal an error.

Signed-off-by: Kirill Makurin <maiddaisuki@outlook.com>
Signed-off-by: LIU Hao <lh_mouse@126.com>
1 file changed