[CircuitCheck] Handle local qubits

[boschmitt]

Description

This PR allows CircuitCheck to verify decompositions that require ancillary qubits. It does this by treating local allocations as ancillas. For example:

// It treat args as non-ancilla
func.func @cccz(%arg0: !quake.ref, %arg1: !quake.ref, %arg2: !quake.ref, %arg3: !quake.ref) {
  %0 = quake.alloca !quake.ref // It will treat it as an ancilla
  //...
}

The resulting unitary for the above circuit will only have 3 qubits (the arguments). CircuitCheck will also check if the ancilla(s) qubit(s) are properly cleaned up, i.e., intermediate results were uncomputed.

[schweitzpgi]

LGTM. I believe we use std::size_t in the rest of the code base.