Add coverage prp

Tasks were selected based on the following criteria:

1. Compiles, if __VERIFIER_X method definitions are provided,
2. No termination property or expected verdict for termination is true, and
3. Some _VERIFIER_nondet* method exists that is not only declared, but used in at least one other location

I selected both tasks with and without memory-errors or overflows - I'm not sure whether this is wanted for Test-Comp, though.