Revert "chase: invert CHASE_NO_AUTOFS and only set it where needed"

This reverts commit 490aa05ca1.

As commented https://github.com/systemd/systemd/pull/38569#discussion_r2284978273,
the commit makes autofs check bypassed. Before the commit, when
CHASE_NO_AUTOFS is set, we did not shortcut chasing paths, and refused
any autofs mount points in the path. However, with the commit, the flag
was swapped but even when CHASE_AUTOFS is unset, the autofs check may be
skipped.

To fix the issue, rather than swapping the flag, we should introduce
another flag, say CHASE_TRIGGER_AUTOFS. This revert the commit, and in a
later commit, the new flag will be introduced.

src/test/test-chase-manual.c

@@ -24,7 +24,7 @@ static int parse_argv(int argc, char *argv[]) {
 
                 { "prefix-root",         no_argument,       NULL, CHASE_PREFIX_ROOT       },
                 { "nonexistent",         no_argument,       NULL, CHASE_NONEXISTENT       },
-                { "autofs",              no_argument,       NULL, CHASE_AUTOFS            },
+                { "no_autofs",           no_argument,       NULL, CHASE_NO_AUTOFS         },
                 { "safe",                no_argument,       NULL, CHASE_SAFE              },
                 { "trail-slash",         no_argument,       NULL, CHASE_TRAIL_SLASH       },
                 { "step",                no_argument,       NULL, CHASE_STEP              },
@@ -60,7 +60,7 @@ static int parse_argv(int argc, char *argv[]) {
 
                 case CHASE_PREFIX_ROOT:
                 case CHASE_NONEXISTENT:
-                case CHASE_AUTOFS:
+                case CHASE_NO_AUTOFS:
                 case CHASE_SAFE:
                 case CHASE_TRAIL_SLASH:
                 case CHASE_STEP: