Fix newstat and newfstat (#2544)
Fix newstat and newfstat (#2544)

## newstat
- Currently `sys_newstat`'s implementation is based on `sys_stat64`
- This is inaccurate because `sys_stat64` is expected to return a `struct stat64` back to userland [ref1](https://elixir.bootlin.com/linux/v5.17.5/source/fs/stat.c#L521) [ref2](https://elixir.bootlin.com/linux/v5.17.5/source/arch/x86/include/uapi/asm/stat.h#L42)
- Instead, `sys_newstat` is supposed to return a `struct stat` [ref1](https://elixir.bootlin.com/linux/v5.17.5/source/fs/stat.c#L380) [ref2](https://elixir.bootlin.com/linux/v5.17.5/source/arch/x86/include/uapi/asm/stat.h#L83)
- This causes issues because the two structs have different definitions, and in practice causes errors in the loader. For example "LD_LIBRARY_PATH" environment variable does not work. I suspect https://github.com/trailofbits/manticore/issues/489 might be related as well but I have yet to test.
- To fix this we can reuse the `sys_newfstat` implementation, which returns the correct `struct stat` structure to userland

## newfstat 
- Currently `sys_newfstat` returns a structure based on the x86_64 version of `struct stat` [ref1](https://elixir.bootlin.com/linux/v5.17.5/source/arch/x86/include/uapi/asm/stat.h#L83)
- This does not account for the different `struct stat` definition on 32-bit x86 [ref1](https://elixir.bootlin.com/linux/v5.17.5/source/arch/x86/include/uapi/asm/stat.h#L10) (Notice the `#ifdef`)
trailofbits/manticore,trailofbits/manticore,trailofbits/manticore