In Jupyter notebook, if simulation ended with runtime exception, allocated qubits are not cleared up

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**Describe the bug**

In Jupyter notebook, if simulation ended with runtime exception, allocated qubits stay around. They show up in the next `DumpMachine` outputs, even though there's no way to access them or clear them up.

**To Reproduce**

```qsharp
open Microsoft.Quantum.Diagnostics;

operation Demo() : Unit {
use q = Qubit();
X(q);
DumpMachine();
}

Demo()
```

As you re-run this code, it throws an exception each time, and the number of allocated qubits grows by 1 each time, all of them in |1> state.

**Expected behavior**

I expect the allocated qubits to not show up in consecutive runs.

**System information**

- qsharp 1.2.0

Run the supplied Demo operation repeatedly in the Jupyter notebook with qsharp 1.2.0 and compare consecutive DumpMachine outputs. Trace what happens to simulator state after the runtime exception; done when qubits from a failed run no longer appear in later outputs or remain inaccessible.

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