unix: Make mem_info() dump GC info too.

mem_info() is already pretty hacky, let it be more hacky.

unix/main.c

@@ -250,6 +250,7 @@ int usage(char **argv) {
 
 mp_obj_t mem_info(void) {
     printf("mem: total=%d, current=%d, peak=%d\n", m_get_total_bytes_allocated(), m_get_current_bytes_allocated(), m_get_peak_bytes_allocated());
+    gc_dump_info();
     return mp_const_none;
 }