Flakes due to np.complex128 to np.complex64 default in unitary change.

[dabacon]

Please add them here.

[verult]

#5611 : CI page

__________________ test_decompose_to_diagonal_and_circuit[v0] __________________
[gw0] linux -- Python 3.8.12 /opt/hostedtoolcache/Python/3.8.12/x64/bin/python
v = array([[-0.21846288-0.1346729j ,  0.15495867+0.10594912j,  0.80196065-0.4123201j , -0.1028374 -0.27418134j],
       [-...[-0.436205  +0.25619444j, -0.22703858+0.4559763j ,  0.11154047+0.18320218j, -0.44752747+0.48820442j]], dtype=complex64)
@pytest.mark.parametrize(
"v",
        [
            cirq.unitary(random_two_qubit_circuit_with_czs(3)),
            cirq.unitary(random_two_qubit_circuit_with_czs(2)),
            np.diag(np.exp(1j * np.pi * np.random.random(4))),
        ],
    )
deftest_decompose_to_diagonal_and_circuit(v):
        b, c = cirq.LineQubit.range(2)
        diagonal, ops = two_qubit_matrix_to_diagonal_and_cz_operations(b, c, v, atol=1e-6)
assert cirq.is_diagonal(diagonal)
        combined_circuit = cirq.Circuit(cirq.MatrixGate(diagonal)(b, c), ops)
        circuit_unitary = combined_circuit.unitary(qubits_that_should_be_present=[b, c])
>       cirq.testing.assert_allclose_up_to_global_phase(circuit_unitary, v, atol=1e-5)
E       AssertionError: 
E       Not equal to tolerance rtol=1e-07, atol=1e-05
E       
E       Mismatched elements: 13 / 16 (81.2%)
E       Max absolute difference: 2.5345644e-05
E       Max relative difference: 0.00044348
E        x: array([[-0.132704-2.196593e-01j,  0.089363+1.650695e-01j,  0.90175 +5.960464e-08j,  0.033925-2.908631e-01j],
E              [-0.41747 -1.450338e-01j,  0.475384+5.262219e-01j, -0.365717+7.906714e-02j,  0.155363-3.710075e-01j],
E              [ 0.673522+1.711057e-01j,  0.045225+4.476309e-01j, -0.026387-1.195236e-02j, -0.469789-3.051746e-01j],
E              [-0.505083+2.837342e-02j, -0.410396+3.017013e-01j,  0.015435+2.139354e-01j, -0.621243+2.295393e-01j]], dtype=complex64)
E        y: array([[-0.132709-2.196612e-01j,  0.089366+1.650790e-01j,  0.901748-2.980232e-08j,  0.033911-2.908625e-01j],
E              [-0.417484-1.450276e-01j,  0.475396+5.[261](https://github.com/quantumlib/Cirq/runs/7049415538?check_suite_focus=true#step:7:262)998e-01j, -0.365723+7.907876e-02j,  0.155345-3.710083e-01j],
E              [ 0.673522+1.710829e-01j,  0.04524 +4.476242e-01j, -0.026399-1.195439e-02j, -0.469803-3.051729e-01j],
E              [-0.505078+2.839129e-02j, -0.410408+3.017058e-01j,  0.015429+2.139305e-01j, -0.621234+2.295500e-01j]], dtype=complex64)
cirq-core/cirq/transformers/analytical_decompositions/two_qubit_to_cz_test.py:[268](https://github.com/quantumlib/Cirq/runs/7049415538?check_suite_focus=true#step:7:269): AssertionError

---

[dabacon]

We have rolled back the change in default #5636 so these should no longer be occurring