[nnkit] Throw bad_alloc on malloc failure (#1624)

[nnkit] Throw bad_alloc on malloc failure (#1624)

tflite backend (for nnsuite conv case) internally uses typed_malloc
method, which wraps std::malloc, which may return nullptr on memory
allocation failure.

This commit revises this method to throw std::bad_alloc on memory
allocation failure (similarly as C++ new) to make it easy to detect
memory allocation failure.

Signed-off-by: Jonghyun Park <jh1302.park@samsung.com>