teensy/lexerfrozen: Make mp_lexer_new_from_file raise an exception.

teensy/lexerfrozen.c

 #include <stdio.h>
 
 #include "py/lexer.h"
+#include "py/runtime.h"
+#include "py/mperrno.h"
 
 mp_import_stat_t mp_import_stat(const char *path) {
     return MP_IMPORT_STAT_NO_EXIST;
 }
 
 mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
-    return NULL;
+    mp_raise_OSError(MP_ENOENT);
 }