Use the correct array of star particles (the selected ones) when writing a snaphot

src/parallel_io.c

@@ -1453,7 +1453,7 @@ void write_output_parallel(struct engine* e, const char* baseName,
                                      Nstars_written);
 
           /* Select the fields to write */
-          stars_write_particles(sparts, list, &num_fields);
+          stars_write_particles(sparts_written, list, &num_fields);
         }
       } break;
 

src/serial_io.c

@@ -1129,7 +1129,7 @@ void write_output_serial(struct engine* e, const char* baseName,
                                          Nstars_written);
 
               /* Select the fields to write */
-              stars_write_particles(sparts, list, &num_fields);
+              stars_write_particles(sparts_written, list, &num_fields);
             }
           } break;
 

src/single_io.c

@@ -949,7 +949,7 @@ void write_output_single(struct engine* e, const char* baseName,
                                      Nstars_written);
 
           /* Select the fields to write */
-          stars_write_particles(sparts, list, &num_fields);
+          stars_write_particles(sparts_written, list, &num_fields);
         }
       } break;