PR #23829: [TFLite] Add options for benchmark_model and label_image to allow fp16 for fp32 models

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Imported from GitHub PR #23829

Add options for benchmark_model and label_image to allow running fp32 models with fp16. Useful when testing NNPAI accelerators with fp16 capability.

Copybara import of the project:

  - b5a99e2174f115f87c0cb3de9d2a2479a0193db2 add cmdline option to allow running fp32 models with fp16 by Koan-Sin Tan <koansin.tan@gmail.com>
  - dc4b9745b41ca7b2a00efb142bb0ab1e9895b4e0 add option for label_image to allow running fp32 models w... by Koan-Sin Tan <koansin.tan@gmail.com>
  - ab7b554405dc4bf5b023522095a9b4a318327e0b rebase and run clang-format by Koan-Sin Tan <koansin.tan@gmail.com>
  - 3042e7a029047d9190a3d37b24771f82017dbbfd Merge ab7b554405dc4bf5b023522095a9b4a318327e0b into 150f7... by freedom" Koan-Sin Tan <koansin.tan@gmail.com>

PiperOrigin-RevId: 235606880