core: check argc/argv uncoditionally

as `assert()` might be dropped with `-DNDEBUG`.

Follow-up to cf3095a and 1637e75.

src/core/main.c

@@ -2726,7 +2726,7 @@ int main(int argc, char *argv[]) {
         Manager *m = NULL;
         FDSet *fds = NULL;
 
-        assert(argc > 0 && !isempty(argv[0]));
+        assert_se(argc > 0 && !isempty(argv[0]));
 
         /* SysV compatibility: redirect init → telinit */
         redirect_telinit(argc, argv);

src/shared/main-func.h

@@ -15,7 +15,7 @@
 #define _DEFINE_MAIN_FUNCTION(intro, impl, ret)                         \
         int main(int argc, char *argv[]) {                              \
                 int r;                                                  \
-                assert(argc > 0 && !isempty(argv[0]));                  \
+                assert_se(argc > 0 && !isempty(argv[0]));               \
                 save_argc_argv(argc, argv);                             \
                 intro;                                                  \
                 r = impl;                                               \