Added polynomial induction variables analysis. With tests.

Rationale:
Information on polynomial sequences is nice to further enhance
BCE and last-value assignment. In this case, this CL enables more
loop optimizations for benchpress' Sum (80 x speedup). Also
changed rem-based geometric induction to wrap-around induction.

Test: test-art-host

Change-Id: Ie4d2659edefb814edda2c971c1f70ba400c31111