Segmentation fault in flatbuffers when parsing malformed modules (#95221)
Fixes #95061, #95062
Add Flatbuffer verification before parsing to avoid crashing on malformed modules. Flatbuffers doesn't perform boundary checks at runtime for the sake of performance, so when parsing untrusted modules it is highly recommended to verify overall buffer integrity.
This bug can be triggered both by C++ (`torch::jit::load`, `torch::jitload_jit_module_from_file`) and Python API (`torch.jit.load`, `torch.jit.jit_module_from_flatbuffer`).
Crash files to reproduce:
[crash-1feb368861083e3d242e5c3fcb1090869f4819c4.txt](https://github.com/pytorch/pytorch/files/10795267/crash-1feb368861083e3d242e5c3fcb1090869f4819c4.txt)
[crash-7e8ffd314223be96b43ca246d3d3481702869455.txt](https://github.com/pytorch/pytorch/files/10795268/crash-7e8ffd314223be96b43ca246d3d3481702869455.txt)
[crash-ad4d7c6183af8f34fe1cb5c8133315c6389c409f.txt](https://github.com/pytorch/pytorch/files/10795279/crash-ad4d7c6183af8f34fe1cb5c8133315c6389c409f.txt)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95221
Approved by: https://github.com/qihqi, https://github.com/davidberard98
