(var == $v) is faster than ($v == var) and scales much better: can they both be that fast?

See:
http://stackoverflow.com/questions/43282665/why-does-the-order-of-how-we-specify-the-variables-in-a-comparison-matter

The ($v == var) filters much later causing a scaling loss.
Investigate if drools can avoid that problem and make the slow one as fast as the fast one.

We don't want to have to rewrite all our rules to take advantage of this speedup and educate all our users to prefer one way over another, if and only if we can avoid it.