Revert "Disable tokenizers on Windows (#13667)" (#13767)

This reverts commit 5afe90d.

This is due to an Meta-internal sync issue - it needs to be reverted and
re-merged.

Author: GregoryComer

install_requirements.py

@@ -112,13 +112,8 @@ def install_requirements(use_pytorch_nightly):
 
     LOCAL_REQUIREMENTS = [
         "third-party/ao",  # We need the latest kernels for fast iteration, so not relying on pypi.
-    ] + (
-        [
-            "extension/llm/tokenizers",  # TODO(larryliu0820): Setup a pypi package for this.
-        ]
-        if sys.platform != "win32"
-        else []
-    )  # TODO(gjcomer): Re-enable when buildable on Windows.
+        "extension/llm/tokenizers",  # TODO(larryliu0820): Setup a pypi package for this.
+    ]
 
     # Install packages directly from local copy instead of pypi.
     # This is usually not recommended.