Add new memory management functions for reallocations and etc.

[aleasims]

This is an umbrella issue for expanding zkLLVM set of memory management functions to complete.

Right now we have only malloc and free. This is not enough to handle even growable vectors in both C++ and Rust. We need to support full set of memory management functions in our compilers and assigner.

Tasks:

• Complete set of memory allocation intrinsics zkllvm-circifier#96
• Memory allocators for assigner target must use assigner-specific intrinsics zkllvm-rslang#75
• Implement memory management functions calloc, realloc and aligned_alloc zkllvm-stdlib#13
• Add support for the rest memory management intrinsics zkllvm-assigner#166
• Add examples which use these function (in Rust and C++)