ptez_loader (pytorch#3897)

Summary:
Pull Request resolved: pytorch#3897

This diff creates a data loader, called PtezDataLoader, to load ptez file during the runtime.
For this diff, PtezDataLoader is only focusing on loading from disk every time we invoke Load function.

Reviewed By: tarun292

Differential Revision: D58133351

fbshipit-source-id: a2a8bdd55c36eed5faafb12613d5ad061b19f1a1

extension/testing_util/targets.bzl

@@ -15,5 +15,6 @@ def define_common_targets():
             "//executorch/extension/data_loader/test/...",
             "//executorch/extension/testing_util/test/...",
             "//executorch/extension/fb/ptez/decompression_methods/test/...",
+            "//executorch/extension/fb/ptez/test/...",
         ],
     )