avoid defining assert function

Call it __VERIFIER_assert instead. Like in the other benchmarks. This
allows tools to include assert.h properly.
loops: initialize uninitalized
bitvector: fix all uninitialized accesses

Now symbiotic gives no false answers on these benchmarks 8-).
ldv: initialize more uninitialized variables
ntdrivers/cdaudio_unsafe.i.cil.c: fix final symbiotic fallout

This is the last one where we give incorrect results. Fix that by
intializing memory that is allocated and accessed without prior
initialization.