Fix forgotten ldv_xmalloc ldv_calloc implementation in some ldv benchmarks

Some ldv benchmarks make use of the ldv_xmalloc and ldv_calloc functions without defining those functions. This MR fixes that (the implementations were taken from ldv-linux-3.14/linux-3.14_complex_emg_linux-kernel-locking-mutex_drivers-net-wireless-airo.cil.i).

Closing #1349 (closed)