Flaky pulse-optimal UnitarySynthesis test with Numpy 1.26

[jakelishman]

Environment

• Qiskit Terra version: 0.45.0
• Python version: 3.8
• Operating system: Linux

What is happening?

CI shows a flaky test with Numpy 1.25+, which was the reason for #11232, and why we can't yet merge #11262. The test is test.python.transpiler.test_unitary_synthesis.TestUnitarySynthesis.test_two_qubit_synthesis_not_pulse_optimal.

How can we reproduce the issue?

Example return from CI:

test.python.transpiler.test_unitary_synthesis.TestUnitarySynthesis.test_two_qubit_synthesis_not_pulse_optimal
-------------------------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/tmp/terra-tests/test/python/transpiler/test_unitary_synthesis.py", line 365, in test_two_qubit_synthesis_not_pulse_optimal
    self.assertGreaterEqual(num_ops["sx"], 16)

      File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/unittest/case.py", line 1275, in assertGreaterEqual
    self.fail(self._formatMessage(msg, standardMsg))

      File "/opt/hostedtoolcache/Python/3.12.0/x64/lib/python3.12/unittest/case.py", line 715, in fail
    raise self.failureException(msg)

    AssertionError: 15 not greater than or equal to 16

What should happen?

Reliable CI.

Any suggestions?

No response