Narrowing gas

[DrMichaelPetter]

Closes #1494 by providing a domain lifter, that applies meet until the gas depletes. In a first application, we get a new parameter ana.apron.narrowing_gas to specify the amount of gas per state, which comes in handy for poyhedra-based analysis.

// SKIP PARAM: --set ana.apron.narrowing_gas 1 --set ana.activated[+] apron --set ana.apron.domain polyhedra
int loop(){
  int i, j, k;
  int a = 0;
  for (i = 500; i >= 1; i--)
  {
    a++;
    __goblint_check(a + i - 501 == 0); // needs 1x narrowing or octagons
  }
  return 0;
}