Crash less and allow more cyclomatic refs

[realFlowControl]

This PR fixes the usage of self referencing closures:

  $fibonacci = function ($n) use (&$fibonacci) {
    if ($n == 0) {
      return 0;
    }
    if ($n == 1) {
      return 1;
    }
    return $fibonacci($n - 1) + $fibonacci($n - 2);
  };

This should also fix some segfaults and/or zend_mm_heap corrupted panics.

Granted, the tests I've added (base/071 and base/072) leak memory, but not much and it does not crash anymore 😉

[mvorisek]

I would expect all memory to he relased no latter than the 1st GC run.

[realFlowControl]

That'd be true "normally", but the memory leaking is not ref counted 😉
The leak is copies I have to create for the closure passed into \parallel\run() to execute it in another thread. So this leak is not referring to user land memory, but extension allocated memory.