[slimtensor] Add SizesAndStrides and dimension utility functions for slimtensor usage

[Gasoonjia]

Stack from ghstack (oldest at bottom):

• rename slimtensor fiies to consistent with executorch files #16469
• [slimtensor] Add utility functions to common_shims_slim #16457
• [slimtensor] Add storage and device property getters to common_shims_slim #16455
• [slimtensor] Add common_shims_slim with basic property getters #16454
• [slimtensor] Add aoti_torch_item_bool for SlimTensor #16453
• [slimtensor] Add aoti_torch_assign_tensors_out for SlimTensor #16452
• [slimtensor] Add aoti_torch_copy_ for SlimTensor #16451
• [slimtensor] Add aoti_torch__reinterpret_tensor for SlimTensor #16450
• [slimtensor] Add aoti_torch_new_tensor_handle for SlimTensor #16449
• [slimtensor] Add aoti_torch_delete_tensor_object for SlimTensor #16448
• [slimtensor] Add SlimTensor-based aoti_torch_empty_strided #16447
• [slimtensor] Add SlimTensor-based aoti_torch_create_tensor_from_blob_v2 #16446
• [slimtensor] Add item() methods with CUDA and CPU support for scalar value extraction #16445
• [slimtensor] Add permute() and reshape() view operations #16444
• [slimtensor] Add as_strided() view operation for tensor reinterpretation #16443
• [slimtensor] Add from_blob() factory function for wrapping external memory #16442
• [slimtensor] Add non-owning storage mode for wrapping external memory #16441
• [slimtensor] Enable CUDA tensor copy #16440
• [slimtensor] Add CUDA slimtensor creation with basic functionality #16439
• [slimtensor] Add CUDA Storage with DeviceTraits and memory allocation #16438
• [slimtensor] Add CUDA DeviceType and extend Device class #16437
• [slimtensor] Add all required dtype support (Int8/16/32/64, Bool, BFloat16) #16399
• [slimtensor] Add factory functions for creating empty CPU tensors #16398
• [slimtensor] Add SlimTensor class with basic properties and CPU copy operation #16385
• -> [slimtensor] Add SizesAndStrides and dimension utility functions for slimtensor usage #16384
• [slimtensor] Storage and SharedPtr for CPU owning mode #16383
• [slimtensor] Introduce Device and ScalarType headers for SlimTensor minimal support #16382

This diff adds the SizesAndStrides class for efficiently storing tensor dimension sizes and strides, along with utility functions for computing element counts and storage requirements.

Key components:

1. c10/macros/Macros.h - Branch prediction hint macros (SLIMTENSOR_LIKELY/UNLIKELY) for optimizing hot paths

2. util/ArrayRefUtil.h - Re-exports ExecuTorch's ArrayRef, IntArrayRef, and makeArrayRef; adds toVec() utility for converting ArrayRef to std::vector

3. c10/core/SizesAndStrides.h - Packed container for tensor sizes and strides:

   • Inline storage for tensors up to 5 dimensions (no heap allocation)
   • Out-of-line heap storage for larger tensors
   • Full copy/move semantics with proper resource management
   • Equality operators and iterators
   • std::initializer_list overloads for convenient initialization

4. util/SizeUtil.h - Size computation utilities:

   • compute_numel() - compute total number of elements
   • compute_contiguous_strides() - compute row-major contiguous strides
   • compute_storage_nbytes() / compute_storage_nbytes_contiguous() - compute storage byte requirements

Differential Revision: D89749336

[pytorch-bot]

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❌ 3 New Failures, 3 Unrelated Failures

As of commit 754c9c4 with merge base fd6fa87 ():

NEW FAILURES - The following jobs have failed:

• pull / test-samsung-models-linux / linux-job (gh)
  RuntimeError: Command docker exec -t 62643894df82467622909bc17f0ee4396cb7bc6340f6746b5bc8e53e0a2c90b0 /exec failed with exit code 1
• pull / test-samsung-quantmodels-linux / linux-job (gh)
  RuntimeError: Command docker exec -t c516472b04bfcac50ad9390bb222e9a84cfb40cce7865116a6c73b26a54d0f65 /exec failed with exit code 1
• Test CUDA Builds / test-models-cuda (add) / linux-job (gh)
  RuntimeError: Command docker exec -t 038ae2116a7c70ac1c4353b3c9be97834c84073dd6e6e687a1ab0e435293bed9 /exec failed with exit code 1

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• pull / test-llama-runner-linux-android / linux-job (gh) (matched linux rule in flaky-rules.json)
  The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.
• pull / test-models-linux-basic (mv3, portable, cmake, linux.2xlarge, executorch-ubuntu-22.04-clang12) / linux-job (gh) (detected as infra flaky with no log or failing log classifier)

UNSTABLE - The following job is marked as unstable, possibly due to flakiness on trunk:

• pull / android / run-emulator (gh) (#16137)
  Timeout waiting for emulator to boot.

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