tree-wide: use pidref_is_self() at more places

src/basic/pidref.c

@@ -429,7 +429,7 @@ int pidref_wait(const PidRef *pidref, siginfo_t *ret, int options) {
         if (pidref_is_remote(pidref))
                 return -EREMOTE;
 
-        if (pidref->pid == 1 || pidref->pid == getpid_cached())
+        if (pidref->pid == 1 || pidref_is_self(pidref))
                 return -ECHILD;
 
         siginfo_t si = {};

src/libsystemd/sd-bus/test-bus-peersockaddr.c

@@ -81,7 +81,7 @@ static void *server(void *p) {
                 _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
 
                 assert_se(pidref_set_pidfd_take(&pidref, pidfd) >= 0);
-                assert_se(pidref.pid == getpid_cached());
+                assert_se(pidref_is_self(&pidref));
         }
 
         const gid_t *gl = NULL;

src/login/logind-dbus.c

@@ -879,7 +879,7 @@ static int create_session(
         if (r < 0)
                 return r;
 
-        if (leader.pid == 1 || leader.pid == getpid_cached())
+        if (leader.pid == 1 || pidref_is_self(&leader))
                 return sd_bus_error_set(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid leader PID");
 
         if (isempty(type))