keep original model_devi.out files for pimd (#1472)

Author: Yi-FanLi

dpgen/generator/run.py

@@ -2185,8 +2185,6 @@ def _read_model_devi_file(
             model_devi_content.shape[0] == model_devi_contents[0].shape[0]
             for model_devi_content in model_devi_contents
         ), "Not all beads generated the same number of lines in the model_devi$\{ibead\}.out file. Check your pimd task carefully."
-        for file in model_devi_files_sorted:
-            os.remove(file)
         last_step = model_devi_contents[0][-1, 0]
         for ibead in range(1, num_beads):
             model_devi_contents[ibead][:, 0] = model_devi_contents[ibead][