Mispredictions for PowerTraceConstraint.

There is a bug in the reformulation framwork. I created a new branch extend_testbench with a new test ptest_power.py. This fails on both python2 and python3, raising the following error (which suggests a bug in the reformulation framework):

RuntimeError: PowerTraceReformulation failed to produce a problem with the expected footprint:
EXPECTED: Max AffineExpression[shape=(1, 1)|constant=False|nonneg=False] subject to 1 AffineConstraint[length=3], 2 RSOCConstraint[length=1] using 1 RealVariable[rank=3], 2 RealVariable[rank=1] variables.
OUTCOME : Max AffineExpression[shape=(1, 1)|constant=False|nonneg=False] subject to 1 AffineConstraint[length=3], 1 ConvexQuadraticConstraint[qterms=1|rank=1|haslin=True], 1 ConicQuadraticConstraint[qterms=2|conic_length=1|rotated=True] using 1 RealVariable[rank=3], 2 RealVariable[rank=1] variables.
This is a bug; please report it to the PICOS developers. You can disable the 'verify_prediction' option to try solving anyway.