Simulate and benchmark two-qubit XEB circuits.

This uses the estimator from cirq.experiments.fidelity_estimation.least_squares_xeb_fidelity_from_expectations, but adapted for use on pandas DataFrames for efficient vectorized operation.

sampled_df: The sampled results to benchmark. This is likely produced by a call to sample_2q_xeb_circuits.
circuits The library of circuits corresponding to the sampled results in sampled_df.
cycle_depths The sequence of cycle depths to simulate the circuits.
param_resolver If circuits contain parameters, resolve according to this ParamResolver prior to simulation
pool If provided, execute the simulations in parallel.

A DataFrame with columns 'cycle_depth' and 'fidelity'.