Add early exit in the limit heuristics() for "bad" results with oo

    This does limit calculations in this method more
    fragle, which is good.  An example:
    >>> O(sin(1/x**2).contains(O(cos(1/x**2)))
    True
    was wrong, just because of this limit:
    >>> limit(sin(1/x**2)/cos(1/x**2), x, 0)
    sin(oo)/cos(oo)
Merge pull request #2928 from skirpichev/contains-use-gruntz

Add early exit in the limit heuristics() for "bad" results with oo