ggml/gguf : prevent integer overflows (llama/19856)

ggml/gguf : prevent integer overflows (llama/19856)

* gguf : prevent integer overflow for ggml_context mem size

* ggml : fix int overflows in ggml_new_object()

* gguf : prevent string exhaustion

* gguf : prevent array elements exhaustion

* ggml : fix negative tensor type oob

* py : assert that alignment is non-zero power of 2

* ggml : check int overflow in ggml_new_tensor_impl and ggml_new_object

* gguf-py : error on duplicate keys when reading

* py : restore tensor_fields

* enforce proper alignment in add_custom_alignment

* gguf : better name

* gguf : fix ctx size for no_alloc == true

* gguf : minor print fix

* ggml : print values when overflow

* ggml : remove deprecated ggml_type_sizef()

* ggml : relax ggml_type asserts to debug-only

* gguf : add mem_size overflow test

* gguf : add file size check for arrays

* ggml : relax asseerts for ggml_get_type_traits()

* flake8 fix

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Co-authored-by: Sigbjørn Skjæret <redacted>