[AOTI] normalize_path_separator file path for Windows. (pytorch#159726)

`normalize_path_separator` file path for Windows.

Pull Request resolved: pytorch#159726
Approved by: https://github.com/angelayi, https://github.com/jansel

Author: xuhancn

torch/export/pt2_archive/_package.py

@@ -12,6 +12,7 @@
 import torch
 import torch.utils._pytree as pytree
 from torch._export.serde.serialize import deserialize, serialize, SerializedArtifact
+from torch._inductor.cpp_builder import normalize_path_separator
 from torch.export import ExportedProgram
 from torch.export._tree_utils import reorder_kwargs
 from torch.export.pt2_archive._package_weights import (
@@ -75,6 +76,8 @@ class PT2ArchiveWriter:
     """
 
     def __init__(self, archive_path_or_buffer: FileLike):
+        if isinstance(archive_path_or_buffer, str):
+            archive_path_or_buffer = normalize_path_separator(archive_path_or_buffer)
         self.archive_file = torch._C.PyTorchFileWriter(archive_path_or_buffer)  # type: ignore[arg-type]
         # NOTICE: version here is different from the archive_version
         # this is the version of zip file format, which is used by PyTorchFileWriter, which write to /.data/version
@@ -169,6 +172,8 @@ class PT2ArchiveReader:
     """
 
     def __init__(self, archive_path_or_buffer: FileLike):
+        if isinstance(archive_path_or_buffer, str):
+            archive_path_or_buffer = normalize_path_separator(archive_path_or_buffer)
         self.archive_file = torch._C.PyTorchFileReader(archive_path_or_buffer)  # type: ignore[arg-type]
         assert self.read_string(ARCHIVE_FORMAT_PATH) == ARCHIVE_FORMAT_VALUE, (
             "Invalid archive format"