Consistent behaviour of StateFn.eval with OperatorBase.eval (Qiskit/qiskit-aqua#1210)
Consistent behaviour of StateFn.eval with OperatorBase.eval (Qiskit/qiskit-aqua#1210)

* eval on a statefn returns the sampling probs

* add tests, rm print

* add reno

* return VectorStateFn instead of Statevector

* Change test case to use ddt instead of subtest loop

Co-authored-by: Manoel Marques <ea0e1aac252908b77f7a6302e9c3d004f36f7b3f@ibm.com>
Co-authored-by: Steve Wood <df319c8b10182f101be29ecf0d4d148dec6c4bfc@users.noreply.github.com>
Co-authored-by: woodsp <28663438367c26797e046d120819e21a96771688@us.ibm.com>
QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py