Fix Windows build failure after DDP PR merged (#45335)

Summary:
Fixes #{issue number}
This is resubmit for PR https://github.com/pytorch/pytorch/issues/42897 . Together with fix for Windows build issue introduced by PR https://github.com/pytorch/pytorch/issues/44344 .

Pull Request resolved: https://github.com/pytorch/pytorch/pull/45335

Reviewed By: zou3519

Differential Revision: D23931471

Pulled By: mrshenli

fbshipit-source-id: f49b5a114944c1450b32934b3292170be064f494
diff --git a/tools/build_variables.bzl b/tools/build_variables.bzl
index 0b67072..ba73e5d 100644
--- a/tools/build_variables.bzl
+++ b/tools/build_variables.bzl
@@ -542,11 +542,14 @@
     "torch/csrc/utils/disable_torch_function.cpp",
 ]
 
-libtorch_python_distributed_sources = [
-    "torch/csrc/distributed/autograd/init.cpp",
+libtorch_python_distributed_core_sources = [
     "torch/csrc/distributed/c10d/comm.cpp",
     "torch/csrc/distributed/c10d/init.cpp",
     "torch/csrc/distributed/c10d/reducer.cpp",
+]
+
+libtorch_python_distributed_sources = libtorch_python_distributed_core_sources + [
+    "torch/csrc/distributed/autograd/init.cpp",
     "torch/csrc/distributed/rpc/init.cpp",
     "torch/csrc/distributed/rpc/process_group_agent.cpp",
     "torch/csrc/distributed/rpc/py_rref.cpp",