Equality: less automatic simplification and fix 'Eq(p, 0)' for p positive

update: no longer on top of #7959 and #7838.
> but you omit much more important is_real

I don't think it should have this.  If is_real is None, we need to let .equals(0) try to figure it out...  It wasn't there before.  

OTOH, we can take a shortcut if is_real is False at this point?

Without splitting this into "_Ineq._eval_simplify" and "Eq._eval_simplify" its a bit tricky to think through these different cases.  Perhaps that a good argument to split!