WaitGate on multiple qubits gets confused about num_qubits when resolved

[zchen088]

Description of the issue
WaitGate.num_qubits() appears to mutate when going through parameter resolution.

How to reproduce the issue

g = cirq.wait(cirq.LineQubit(1), cirq.LineQubit(2))
cirq.resolve_parameters(g, {'a': 1})

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/protocols/resolve_parameters.py:184, in resolve_parameters(val, param_resolver, recursive) 182 result = NotImplemented 183 else: --> 184 result = getter(param_resolver, recursive) 186 if result is not NotImplemented: 187 return result

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/ops/gate_operation.py:278, in GateOperation.resolve_parameters(self, resolver, recursive)
274 def resolve_parameters(
275 self, resolver: 'cirq.ParamResolver', recursive: bool
276 ) -> 'cirq.Operation':
277 resolved_gate = protocols.resolve_parameters(self.gate, resolver, recursive)
--> 278 return self.with_gate(resolved_gate)

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/ops/gate_operation.py:82, in GateOperation.with_gate(self, new_gate)
79 if self.gate is new_gate:
80 # As GateOperation is immutable, this can return the original.
81 return self
---> 82 return new_gate.on(*self.qubits)

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/ops/raw_types.py:219, in Gate.on(self, *qubits)
213 def on(self, *qubits: Qid) -> 'Operation':
214 """Returns an application of this gate to the given qubits.
215
216 Args:
217 *qubits: The collection of qubits to potentially apply the gate to.
218 """
--> 219 return ops.gate_operation.GateOperation(self, list(qubits))

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/ops/gate_operation.py:61, in GateOperation.init(self, gate, qubits)
54 def init(self, gate: 'cirq.Gate', qubits: Sequence['cirq.Qid']) -> None:
55 """Inits GateOperation.
56
57 Args:
58 gate: The gate to apply.
59 qubits: The qubits to operate on.
60 """
---> 61 gate.validate_args(qubits)
62 self._gate = gate
63 self._qubits = tuple(qubits)

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/ops/raw_types.py:211, in Gate.validate_args(self, qubits)
194 def validate_args(self, qubits: Sequence['cirq.Qid']) -> None:
195 """Checks if this gate can be applied to the given qubits.
196
197 By default checks that:
(...)
209 ValueError: The gate can't be applied to the qubits.
210 """
--> 211 _validate_qid_shape(self, qubits)

File ~/.virtualenvs/pyle/lib/python3.8/site-packages/cirq/ops/raw_types.py:929, in _validate_qid_shape(val, qubits)
927 qid_shape = protocols.qid_shape(val)
928 if len(qubits) != len(qid_shape):
--> 929 raise ValueError(
930 'Wrong number of qubits for <{!r}>. '
931 'Expected {} qubits but got <{!r}>.'.format(val, len(qid_shape), qubits)
932 )
933 if any(qid.dimension != dimension for qid, dimension in zip(qubits, qid_shape)):
934 raise ValueError(
935 'Wrong shape of qids for <{!r}>. '
936 'Expected {} but got {} <{!r}>.'.format(
937 val, qid_shape, tuple(qid.dimension for qid in qubits), qubits
938 )
939 )

ValueError: Wrong number of qubits for <cirq.WaitGate(cirq.Duration(millis=0))>. Expected 1 qubits but got <[cirq.LineQubit(1), cirq.LineQubit(2)]>.

Cirq version
'0.15.0.dev20220503224557'