cirq-google: Remove serializers (quantumlib#5764)

First few commits are from quantumlib#5762

@dstrain115

Author: verult

cirq-google/cirq_google/__init__.py

@@ -111,12 +111,8 @@
     CIRCUIT_SERIALIZER,
     CircuitSerializer,
     CircuitOpDeserializer,
-    DeserializingArg,
-    GateOpDeserializer,
     CircuitOpSerializer,
-    GateOpSerializer,
     Serializer,
-    SerializingArg,
 )
 
 from cirq_google.workflow import (

cirq-google/cirq_google/json_test_data/spec.py

@@ -26,21 +26,17 @@
         'ConvertToSqrtIswapGates',
         'ConvertToSycamoreGates',
         'ConvertToXmonGates',
-        'DeserializingArg',
         'Engine',
         'EngineJob',
         'EngineProcessor',
         'EngineProgram',
         'FSimPhaseCorrections',
         'NoiseModelFromGoogleNoiseProperties',
         'ProtoVersion',
-        'GateOpSerializer',
-        'GateOpDeserializer',
         'GreedySequenceSearchStrategy',
         'PhasedFSimCalibrationError',
         'PhasedFSimEngineSimulator',
         'PerQubitDepolarizingWithDampedReadoutNoiseModel',
-        'SerializingArg',
         'THETA_ZETA_GAMMA_FLOQUET_PHASED_FSIM_CHARACTERIZATION',
         'ProcessorSampler',
         'ValidatingSampler',

cirq-google/cirq_google/serialization/__init__.py

@@ -16,19 +16,10 @@
 
 from cirq_google.serialization.arg_func_langs import arg_from_proto
 
-
 from cirq_google.serialization.circuit_serializer import CircuitSerializer, CIRCUIT_SERIALIZER
 
-from cirq_google.serialization.op_deserializer import (
-    CircuitOpDeserializer,
-    DeserializingArg,
-    GateOpDeserializer,
-)
+from cirq_google.serialization.op_deserializer import CircuitOpDeserializer
 
-from cirq_google.serialization.op_serializer import (
-    CircuitOpSerializer,
-    GateOpSerializer,
-    SerializingArg,
-)
+from cirq_google.serialization.op_serializer import CircuitOpSerializer
 
 from cirq_google.serialization.serializer import Serializer