OptimizeSwapBeforeMeasure should only affect last measurements, not mid-circuit measurements

[1ucian0]

In a tangentially related PR review, @kdk noticed that OptimizeSwapBeforeMeasure is broken when using mid-circuit measurements.

For example:

from qiskit import QuantumCircuit, QuantumRegister, ClassicalRegister
from qiskit.transpiler.passes import OptimizeSwapBeforeMeasure

qr1 = QuantumRegister(1, 'qr1')
qr2 = QuantumRegister(2, 'qr2')
cr = ClassicalRegister(3, 'cr')
circuit = QuantumCircuit(qr1, qr2, cr)
circuit.h(qr1[0])
circuit.h(qr2[1])
circuit.swap(qr1[0], qr2[0])
circuit.measure(qr1[0], cr[0])
circuit.measure(qr2[0], cr[1])
circuit.measure(qr2[1], cr[2])
circuit.cx(qr1[0], qr2[ 1])
circuit.swap(qr1[0], qr2[0])
circuit.measure(qr1[0], cr[0])
circuit.measure(qr2[0], cr[1])
circuit.measure(qr2[1], cr[2])


print(circuit)
print(OptimizeSwapBeforeMeasure()(circuit))

       ┌───┐   ┌─┐           ┌─┐
qr1_0: ┤ H ├─X─┤M├─────■───X─┤M├───
       └───┘ │ └╥┘┌─┐  │   │ └╥┘┌─┐
qr2_0: ──────X──╫─┤M├──┼───X──╫─┤M├
       ┌───┐┌─┐ ║ └╥┘┌─┴─┐┌─┐ ║ └╥┘
qr2_1: ┤ H ├┤M├─╫──╫─┤ X ├┤M├─╫──╫─
       └───┘└╥┘ ║  ║ └───┘└╥┘ ║  ║
 cr: 3/══════╩══╩══╩═══════╩══╩══╩═
             2  0  1       2  0  1
       ┌───┐              ┌─┐   ┌─┐
qr1_0: ┤ H ├───────────■──┤M├───┤M├
       └───┘┌─┐┌─┐     │  └╥┘   └╥┘
qr2_0: ─────┤M├┤M├─────┼───╫─────╫─
       ┌───┐└╥┘└╥┘┌─┐┌─┴─┐ ║ ┌─┐ ║
qr2_1: ┤ H ├─╫──╫─┤M├┤ X ├─╫─┤M├─╫─
       └───┘ ║  ║ └╥┘└───┘ ║ └╥┘ ║
 cr: 3/══════╩══╩══╩═══════╩══╩══╩═
             0  0  2       1  2  1

The expected result is that OptimizeSwapBeforeMeasure should only affect "final" measurements.

[jakelishman]

This is no longer reproducible as of Qiskit 1.0.0 - probably it was fixed by #11413.