[ET Device Support] Parse device info from serialized tensor in tensor_parser

[Gasoonjia]

Stack from ghstack (oldest at bottom):

• [ET Device Support] Add NonConstBufferDevice schema for per-buffer device mapping #18330
• [ET Device Support] DeviceAllocator interface and DeviceAllocatorRegistry #17535
• [ET Device Support] Annotate device attributes of CUDA backend IO tensors cuda device #18080
• -> [ET Device Support] Parse device info from serialized tensor in tensor_parser #18328
• [ET Device Support] Propagate device info from TensorSpec into serialized Tensor #18079
• [executorch] Propagate device metadata from partitioner result onto TensorSpecs #18078
• [ET Device Support] TensorImpl carries device info #17534
• [ET Device Support] Schema changes: device info on Tensor and buffer-level device array #17533

Parse device info (device_type, device_index) from the serialized ExtraTensorInfo in .pte files into TensorImpl at runtime.
When a tensor's extra_tensor_info contains device annotations (e.g., CUDA), the tensor parser now reads and propagates them to the TensorImpl constructor. Tensors without extra_tensor_info default to CPU/0 for backward compatibility with older PTE files.、

Differential Revision: D97199497

[pytorch-bot]

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❌ 1 New Failure, 2 Unrelated Failures

As of commit b18f298 with merge base bf2243a ():

NEW FAILURE - The following job has failed:

• pull / test-multimodal-linux (gemma3-4b) / linux-job (gh)
  RuntimeError: Command docker exec -t 05a1e4c418e356ffdf7050e8a3fdac45b2c84ddb07ff3beb433c3329c22d1689 /exec failed with exit code 139

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

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